Squashed 'vendor/ruvector/' content from commit b64c2172

git-subtree-dir: vendor/ruvector
git-subtree-split: b64c21726f2bb37286d9ee36a7869fef60cc6900

examples/scipix/tests/unit/config_tests.rs

@@ -0,0 +1,372 @@
+// Configuration tests for ruvector-scipix
+//
+// Tests configuration loading, serialization, validation, and defaults.
+// Target: 90%+ coverage of config module
+
+#[cfg(test)]
+mod config_tests {
+    use std::path::PathBuf;
+
+    // Mock configuration structures for testing
+    #[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+    struct PreprocessConfig {
+        target_dpi: u32,
+        max_dimension: u32,
+        denoise_strength: f32,
+        contrast_enhancement: bool,
+        auto_rotate: bool,
+        binarization_method: String,
+    }
+
+    #[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+    struct OcrModelConfig {
+        model_path: PathBuf,
+        device: String,
+        batch_size: usize,
+        confidence_threshold: f32,
+    }
+
+    #[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+    struct OutputConfig {
+        format: String,
+        include_confidence: bool,
+        include_geometry: bool,
+    }
+
+    #[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
+    struct ScipixConfig {
+        preprocessing: PreprocessConfig,
+        model: OcrModelConfig,
+        output: OutputConfig,
+    }
+
+    impl Default for PreprocessConfig {
+        fn default() -> Self {
+            Self {
+                target_dpi: 300,
+                max_dimension: 4096,
+                denoise_strength: 0.5,
+                contrast_enhancement: true,
+                auto_rotate: true,
+                binarization_method: "adaptive".to_string(),
+            }
+        }
+    }
+
+    impl Default for OcrModelConfig {
+        fn default() -> Self {
+            Self {
+                model_path: PathBuf::from("models/scipix_model.onnx"),
+                device: "cpu".to_string(),
+                batch_size: 4,
+                confidence_threshold: 0.7,
+            }
+        }
+    }
+
+    impl Default for OutputConfig {
+        fn default() -> Self {
+            Self {
+                format: "latex".to_string(),
+                include_confidence: true,
+                include_geometry: false,
+            }
+        }
+    }
+
+    impl Default for ScipixConfig {
+        fn default() -> Self {
+            Self {
+                preprocessing: PreprocessConfig::default(),
+                model: OcrModelConfig::default(),
+                output: OutputConfig::default(),
+            }
+        }
+    }
+
+    #[test]
+    fn test_default_config_creation() {
+        let config = ScipixConfig::default();
+
+        assert_eq!(config.preprocessing.target_dpi, 300);
+        assert_eq!(config.model.device, "cpu");
+        assert_eq!(config.output.format, "latex");
+    }
+
+    #[test]
+    fn test_preprocessing_config_defaults() {
+        let config = PreprocessConfig::default();
+
+        assert_eq!(config.target_dpi, 300);
+        assert_eq!(config.max_dimension, 4096);
+        assert_eq!(config.denoise_strength, 0.5);
+        assert!(config.contrast_enhancement);
+        assert!(config.auto_rotate);
+        assert_eq!(config.binarization_method, "adaptive");
+    }
+
+    #[test]
+    fn test_model_config_defaults() {
+        let config = OcrModelConfig::default();
+
+        assert_eq!(config.model_path, PathBuf::from("models/scipix_model.onnx"));
+        assert_eq!(config.device, "cpu");
+        assert_eq!(config.batch_size, 4);
+        assert_eq!(config.confidence_threshold, 0.7);
+    }
+
+    #[test]
+    fn test_output_config_defaults() {
+        let config = OutputConfig::default();
+
+        assert_eq!(config.format, "latex");
+        assert!(config.include_confidence);
+        assert!(!config.include_geometry);
+    }
+
+    #[test]
+    fn test_toml_serialization() {
+        let config = ScipixConfig::default();
+
+        let toml_str = toml::to_string(&config).expect("Failed to serialize to TOML");
+
+        assert!(toml_str.contains("target_dpi = 300"));
+        assert!(toml_str.contains("device = \"cpu\""));
+        assert!(toml_str.contains("format = \"latex\""));
+    }
+
+    #[test]
+    fn test_toml_deserialization() {
+        let toml_str = r#"
+            [preprocessing]
+            target_dpi = 300
+            max_dimension = 4096
+            denoise_strength = 0.5
+            contrast_enhancement = true
+            auto_rotate = true
+            binarization_method = "adaptive"
+
+            [model]
+            model_path = "models/scipix_model.onnx"
+            device = "cpu"
+            batch_size = 4
+            confidence_threshold = 0.7
+
+            [output]
+            format = "latex"
+            include_confidence = true
+            include_geometry = false
+        "#;
+
+        let config: ScipixConfig = toml::from_str(toml_str).expect("Failed to deserialize TOML");
+
+        assert_eq!(config.preprocessing.target_dpi, 300);
+        assert_eq!(config.model.device, "cpu");
+        assert_eq!(config.output.format, "latex");
+    }
+
+    #[test]
+    fn test_json_serialization() {
+        let config = ScipixConfig::default();
+
+        let json_str = serde_json::to_string(&config).expect("Failed to serialize to JSON");
+
+        assert!(json_str.contains("\"target_dpi\":300"));
+        assert!(json_str.contains("\"device\":\"cpu\""));
+    }
+
+    #[test]
+    fn test_json_deserialization() {
+        let json_str = r#"{
+            "preprocessing": {
+                "target_dpi": 300,
+                "max_dimension": 4096,
+                "denoise_strength": 0.5,
+                "contrast_enhancement": true,
+                "auto_rotate": true,
+                "binarization_method": "adaptive"
+            },
+            "model": {
+                "model_path": "models/scipix_model.onnx",
+                "device": "cpu",
+                "batch_size": 4,
+                "confidence_threshold": 0.7
+            },
+            "output": {
+                "format": "latex",
+                "include_confidence": true,
+                "include_geometry": false
+            }
+        }"#;
+
+        let config: ScipixConfig =
+            serde_json::from_str(json_str).expect("Failed to deserialize JSON");
+
+        assert_eq!(config.preprocessing.target_dpi, 300);
+        assert_eq!(config.model.device, "cpu");
+    }
+
+    #[test]
+    fn test_preset_configurations() {
+        // High quality preset
+        let high_quality = ScipixConfig {
+            preprocessing: PreprocessConfig {
+                target_dpi: 600,
+                denoise_strength: 0.8,
+                ..Default::default()
+            },
+            model: OcrModelConfig {
+                confidence_threshold: 0.9,
+                ..Default::default()
+            },
+            ..Default::default()
+        };
+
+        assert_eq!(high_quality.preprocessing.target_dpi, 600);
+        assert_eq!(high_quality.model.confidence_threshold, 0.9);
+
+        // Fast preset
+        let fast = ScipixConfig {
+            preprocessing: PreprocessConfig {
+                target_dpi: 150,
+                contrast_enhancement: false,
+                auto_rotate: false,
+                ..Default::default()
+            },
+            model: OcrModelConfig {
+                batch_size: 8,
+                confidence_threshold: 0.5,
+                ..Default::default()
+            },
+            ..Default::default()
+        };
+
+        assert_eq!(fast.preprocessing.target_dpi, 150);
+        assert_eq!(fast.model.batch_size, 8);
+    }
+
+    #[test]
+    fn test_config_validation_valid() {
+        let config = ScipixConfig::default();
+
+        // Basic validation checks
+        assert!(config.preprocessing.target_dpi > 0);
+        assert!(config.preprocessing.max_dimension > 0);
+        assert!(config.preprocessing.denoise_strength >= 0.0);
+        assert!(config.preprocessing.denoise_strength <= 1.0);
+        assert!(config.model.batch_size > 0);
+        assert!(config.model.confidence_threshold >= 0.0);
+        assert!(config.model.confidence_threshold <= 1.0);
+    }
+
+    #[test]
+    fn test_config_validation_invalid_values() {
+        // Test invalid DPI
+        let mut config = ScipixConfig::default();
+        config.preprocessing.target_dpi = 0;
+        assert_eq!(config.preprocessing.target_dpi, 0); // Would fail validation
+
+        // Test invalid confidence threshold
+        config = ScipixConfig::default();
+        config.model.confidence_threshold = 1.5;
+        assert!(config.model.confidence_threshold > 1.0); // Would fail validation
+    }
+
+    #[test]
+    fn test_environment_variable_overrides() {
+        // Simulate environment variable overrides
+        let mut config = ScipixConfig::default();
+
+        // Override device from environment
+        let env_device = std::env::var("MATHPIX_DEVICE").unwrap_or_else(|_| "cpu".to_string());
+        config.model.device = env_device;
+
+        // Override batch size from environment
+        let env_batch_size = std::env::var("MATHPIX_BATCH_SIZE")
+            .ok()
+            .and_then(|s| s.parse::<usize>().ok())
+            .unwrap_or(config.model.batch_size);
+        config.model.batch_size = env_batch_size;
+
+        assert!(!config.model.device.is_empty());
+        assert!(config.model.batch_size > 0);
+    }
+
+    #[test]
+    fn test_config_cloning() {
+        let config1 = ScipixConfig::default();
+        let config2 = config1.clone();
+
+        assert_eq!(config1, config2);
+        assert_eq!(
+            config1.preprocessing.target_dpi,
+            config2.preprocessing.target_dpi
+        );
+    }
+
+    #[test]
+    fn test_partial_config_update() {
+        let mut config = ScipixConfig::default();
+
+        // Update only preprocessing settings
+        config.preprocessing.target_dpi = 450;
+        config.preprocessing.denoise_strength = 0.7;
+
+        assert_eq!(config.preprocessing.target_dpi, 450);
+        assert_eq!(config.preprocessing.denoise_strength, 0.7);
+        // Other settings should remain default
+        assert_eq!(config.model.device, "cpu");
+        assert_eq!(config.output.format, "latex");
+    }
+
+    #[test]
+    fn test_binarization_methods() {
+        let methods = vec!["otsu", "adaptive", "sauvola", "niblack"];
+
+        for method in methods {
+            let mut config = PreprocessConfig::default();
+            config.binarization_method = method.to_string();
+            assert_eq!(config.binarization_method, method);
+        }
+    }
+
+    #[test]
+    fn test_output_formats() {
+        let formats = vec!["latex", "mathml", "mmd", "ascii", "unicode"];
+
+        for format in formats {
+            let mut config = OutputConfig::default();
+            config.format = format.to_string();
+            assert_eq!(config.format, format);
+        }
+    }
+
+    #[test]
+    fn test_device_configurations() {
+        let devices = vec!["cpu", "cuda", "cuda:0", "cuda:1"];
+
+        for device in devices {
+            let mut config = OcrModelConfig::default();
+            config.device = device.to_string();
+            assert_eq!(config.device, device);
+        }
+    }
+
+    #[test]
+    fn test_config_roundtrip_toml() {
+        let original = ScipixConfig::default();
+        let toml_str = toml::to_string(&original).unwrap();
+        let deserialized: ScipixConfig = toml::from_str(&toml_str).unwrap();
+
+        assert_eq!(original, deserialized);
+    }
+
+    #[test]
+    fn test_config_roundtrip_json() {
+        let original = ScipixConfig::default();
+        let json_str = serde_json::to_string(&original).unwrap();
+        let deserialized: ScipixConfig = serde_json::from_str(&json_str).unwrap();
+
+        assert_eq!(original, deserialized);
+    }
+}

examples/scipix/tests/unit/error_tests.rs

@@ -0,0 +1,344 @@
+// Error handling tests for ruvector-scipix
+//
+// Tests error types, conversions, display messages, and retry logic.
+// Target: 95%+ coverage of error handling code
+
+#[cfg(test)]
+mod error_tests {
+    use std::fmt;
+    use std::io;
+
+    // Mock error types for testing
+    #[derive(Debug, Clone, PartialEq)]
+    enum ScipixError {
+        // Image errors
+        InvalidImageFormat(String),
+        ImageTooLarge { size: u64, max: u64 },
+        ImagePreprocessingFailed(String),
+        ImageLoadError(String),
+
+        // Model errors
+        ModelNotFound(String),
+        ModelLoadError(String),
+        InferenceError(String),
+
+        // OCR errors
+        TextDetectionFailed(String),
+        TextRecognitionFailed(String),
+        LowConfidence { score: f32, threshold: f32 },
+
+        // Math parsing errors
+        ParseError(String),
+        InvalidExpression(String),
+
+        // I/O errors
+        IoError(String),
+
+        // API errors
+        ApiError { status: u16, message: String },
+        RateLimitExceeded,
+
+        // System errors
+        Timeout(std::time::Duration),
+        OutOfMemory,
+        Internal(String),
+    }
+
+    impl fmt::Display for ScipixError {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            match self {
+                Self::InvalidImageFormat(format) => {
+                    write!(f, "Invalid image format: {}", format)
+                }
+                Self::ImageTooLarge { size, max } => {
+                    write!(f, "Image too large: {} bytes (max: {} bytes)", size, max)
+                }
+                Self::ImagePreprocessingFailed(reason) => {
+                    write!(f, "Image preprocessing failed: {}", reason)
+                }
+                Self::ImageLoadError(msg) => write!(f, "Failed to load image: {}", msg),
+                Self::ModelNotFound(model) => write!(f, "Model not found: {}", model),
+                Self::ModelLoadError(msg) => write!(f, "Failed to load model: {}", msg),
+                Self::InferenceError(msg) => write!(f, "Model inference failed: {}", msg),
+                Self::TextDetectionFailed(msg) => write!(f, "Text detection failed: {}", msg),
+                Self::TextRecognitionFailed(msg) => {
+                    write!(f, "Text recognition failed: {}", msg)
+                }
+                Self::LowConfidence { score, threshold } => write!(
+                    f,
+                    "Low confidence score: {:.2} (threshold: {:.2})",
+                    score, threshold
+                ),
+                Self::ParseError(msg) => write!(f, "Parse error: {}", msg),
+                Self::InvalidExpression(expr) => write!(f, "Invalid expression: {}", expr),
+                Self::IoError(msg) => write!(f, "I/O error: {}", msg),
+                Self::ApiError { status, message } => {
+                    write!(f, "API error {}: {}", status, message)
+                }
+                Self::RateLimitExceeded => write!(f, "Rate limit exceeded"),
+                Self::Timeout(duration) => write!(f, "Operation timed out after {:?}", duration),
+                Self::OutOfMemory => write!(f, "Out of memory"),
+                Self::Internal(msg) => write!(f, "Internal error: {}", msg),
+            }
+        }
+    }
+
+    impl std::error::Error for ScipixError {}
+
+    impl From<io::Error> for ScipixError {
+        fn from(err: io::Error) -> Self {
+            Self::IoError(err.to_string())
+        }
+    }
+
+    impl ScipixError {
+        fn is_retryable(&self) -> bool {
+            matches!(
+                self,
+                Self::Timeout(_)
+                    | Self::ApiError { status: 503, .. }
+                    | Self::ApiError { status: 429, .. }
+                    | Self::InferenceError(_)
+            )
+        }
+
+        fn status_code(&self) -> Option<u16> {
+            match self {
+                Self::InvalidImageFormat(_) => Some(400),
+                Self::ImageTooLarge { .. } => Some(413),
+                Self::ModelNotFound(_) => Some(404),
+                Self::RateLimitExceeded => Some(429),
+                Self::ApiError { status, .. } => Some(*status),
+                Self::Timeout(_) => Some(408),
+                Self::OutOfMemory => Some(507),
+                _ => Some(500),
+            }
+        }
+    }
+
+    #[test]
+    fn test_error_creation() {
+        let err = ScipixError::InvalidImageFormat("svg".to_string());
+        assert_eq!(
+            err,
+            ScipixError::InvalidImageFormat("svg".to_string())
+        );
+    }
+
+    #[test]
+    fn test_error_display_invalid_format() {
+        let err = ScipixError::InvalidImageFormat("svg".to_string());
+        assert_eq!(err.to_string(), "Invalid image format: svg");
+    }
+
+    #[test]
+    fn test_error_display_image_too_large() {
+        let err = ScipixError::ImageTooLarge {
+            size: 15_000_000,
+            max: 10_000_000,
+        };
+        assert_eq!(
+            err.to_string(),
+            "Image too large: 15000000 bytes (max: 10000000 bytes)"
+        );
+    }
+
+    #[test]
+    fn test_error_display_low_confidence() {
+        let err = ScipixError::LowConfidence {
+            score: 0.65,
+            threshold: 0.8,
+        };
+        assert_eq!(
+            err.to_string(),
+            "Low confidence score: 0.65 (threshold: 0.80)"
+        );
+    }
+
+    #[test]
+    fn test_error_display_api_error() {
+        let err = ScipixError::ApiError {
+            status: 404,
+            message: "Not found".to_string(),
+        };
+        assert_eq!(err.to_string(), "API error 404: Not found");
+    }
+
+    #[test]
+    fn test_error_display_timeout() {
+        let err = ScipixError::Timeout(std::time::Duration::from_secs(30));
+        assert_eq!(err.to_string(), "Operation timed out after 30s");
+    }
+
+    #[test]
+    fn test_io_error_conversion() {
+        let io_err = io::Error::new(io::ErrorKind::NotFound, "file not found");
+        let scipix_err: ScipixError = io_err.into();
+
+        match scipix_err {
+            ScipixError::IoError(msg) => assert!(msg.contains("file not found")),
+            _ => panic!("Expected IoError variant"),
+        }
+    }
+
+    #[test]
+    fn test_is_retryable_timeout() {
+        let err = ScipixError::Timeout(std::time::Duration::from_secs(10));
+        assert!(err.is_retryable());
+    }
+
+    #[test]
+    fn test_is_retryable_503() {
+        let err = ScipixError::ApiError {
+            status: 503,
+            message: "Service Unavailable".to_string(),
+        };
+        assert!(err.is_retryable());
+    }
+
+    #[test]
+    fn test_is_retryable_429() {
+        let err = ScipixError::ApiError {
+            status: 429,
+            message: "Too Many Requests".to_string(),
+        };
+        assert!(err.is_retryable());
+    }
+
+    #[test]
+    fn test_is_not_retryable_404() {
+        let err = ScipixError::ApiError {
+            status: 404,
+            message: "Not Found".to_string(),
+        };
+        assert!(!err.is_retryable());
+    }
+
+    #[test]
+    fn test_is_not_retryable_invalid_format() {
+        let err = ScipixError::InvalidImageFormat("svg".to_string());
+        assert!(!err.is_retryable());
+    }
+
+    #[test]
+    fn test_status_code_invalid_format() {
+        let err = ScipixError::InvalidImageFormat("svg".to_string());
+        assert_eq!(err.status_code(), Some(400));
+    }
+
+    #[test]
+    fn test_status_code_image_too_large() {
+        let err = ScipixError::ImageTooLarge {
+            size: 15_000_000,
+            max: 10_000_000,
+        };
+        assert_eq!(err.status_code(), Some(413));
+    }
+
+    #[test]
+    fn test_status_code_not_found() {
+        let err = ScipixError::ModelNotFound("model.onnx".to_string());
+        assert_eq!(err.status_code(), Some(404));
+    }
+
+    #[test]
+    fn test_status_code_rate_limit() {
+        let err = ScipixError::RateLimitExceeded;
+        assert_eq!(err.status_code(), Some(429));
+    }
+
+    #[test]
+    fn test_status_code_timeout() {
+        let err = ScipixError::Timeout(std::time::Duration::from_secs(30));
+        assert_eq!(err.status_code(), Some(408));
+    }
+
+    #[test]
+    fn test_status_code_out_of_memory() {
+        let err = ScipixError::OutOfMemory;
+        assert_eq!(err.status_code(), Some(507));
+    }
+
+    #[test]
+    fn test_status_code_internal() {
+        let err = ScipixError::Internal("something went wrong".to_string());
+        assert_eq!(err.status_code(), Some(500));
+    }
+
+    #[test]
+    fn test_error_cloning() {
+        let err1 = ScipixError::InvalidImageFormat("svg".to_string());
+        let err2 = err1.clone();
+        assert_eq!(err1, err2);
+    }
+
+    #[test]
+    fn test_multiple_error_types() {
+        let errors = vec![
+            ScipixError::InvalidImageFormat("svg".to_string()),
+            ScipixError::ImageTooLarge {
+                size: 15_000_000,
+                max: 10_000_000,
+            },
+            ScipixError::ModelNotFound("model.onnx".to_string()),
+            ScipixError::RateLimitExceeded,
+            ScipixError::Timeout(std::time::Duration::from_secs(30)),
+        ];
+
+        assert_eq!(errors.len(), 5);
+        for err in &errors {
+            assert!(!err.to_string().is_empty());
+        }
+    }
+
+    #[test]
+    fn test_error_categorization() {
+        let image_errors = vec![
+            ScipixError::InvalidImageFormat("svg".to_string()),
+            ScipixError::ImageTooLarge {
+                size: 15_000_000,
+                max: 10_000_000,
+            },
+            ScipixError::ImagePreprocessingFailed("deskew failed".to_string()),
+        ];
+
+        for err in &image_errors {
+            match err {
+                ScipixError::InvalidImageFormat(_)
+                | ScipixError::ImageTooLarge { .. }
+                | ScipixError::ImagePreprocessingFailed(_) => {
+                    // Image-related errors
+                    assert!(err.status_code().is_some());
+                }
+                _ => panic!("Expected image error"),
+            }
+        }
+    }
+
+    #[test]
+    fn test_retryable_errors_collection() {
+        let errors = vec![
+            ScipixError::Timeout(std::time::Duration::from_secs(30)),
+            ScipixError::ApiError {
+                status: 503,
+                message: "Service Unavailable".to_string(),
+            },
+            ScipixError::InferenceError("temporary failure".to_string()),
+        ];
+
+        let retryable_count = errors.iter().filter(|e| e.is_retryable()).count();
+        assert_eq!(retryable_count, 3);
+    }
+
+    #[test]
+    fn test_non_retryable_errors_collection() {
+        let errors = vec![
+            ScipixError::InvalidImageFormat("svg".to_string()),
+            ScipixError::ModelNotFound("model.onnx".to_string()),
+            ScipixError::ParseError("invalid latex".to_string()),
+        ];
+
+        let retryable_count = errors.iter().filter(|e| e.is_retryable()).count();
+        assert_eq!(retryable_count, 0);
+    }
+}

examples/scipix/tests/unit/math_tests.rs

@@ -0,0 +1,596 @@
+// Math parsing tests for ruvector-scipix
+//
+// Tests symbol recognition, AST construction, and LaTeX/MathML/AsciiMath generation
+// for various mathematical expressions including fractions, roots, matrices, integrals, etc.
+// Target: 90%+ coverage of math parsing module
+
+#[cfg(test)]
+mod math_tests {
+    // Mock math structures for testing
+    #[derive(Debug, Clone, PartialEq)]
+    enum MathSymbol {
+        // Numbers
+        Digit(char),
+
+        // Variables
+        Variable(char),
+
+        // Greek letters
+        Alpha,
+        Beta,
+        Gamma,
+        Delta,
+        Epsilon,
+        Pi,
+        Sigma,
+        Omega,
+
+        // Operators
+        Plus,
+        Minus,
+        Times,
+        Divide,
+        Equals,
+
+        // Relations
+        LessThan,
+        GreaterThan,
+        LessEqual,
+        GreaterEqual,
+        NotEqual,
+
+        // Special symbols
+        Infinity,
+        Partial,
+        Nabla,
+        Integral,
+        Sum,
+        Product,
+        Root,
+        Sqrt,
+
+        // Brackets
+        LeftParen,
+        RightParen,
+        LeftBracket,
+        RightBracket,
+        LeftBrace,
+        RightBrace,
+    }
+
+    #[derive(Debug, Clone, PartialEq)]
+    enum MathNode {
+        Number(String),
+        Variable(String),
+        Symbol(MathSymbol),
+        BinaryOp {
+            op: String,
+            left: Box<MathNode>,
+            right: Box<MathNode>,
+        },
+        Fraction {
+            numerator: Box<MathNode>,
+            denominator: Box<MathNode>,
+        },
+        Superscript {
+            base: Box<MathNode>,
+            exponent: Box<MathNode>,
+        },
+        Subscript {
+            base: Box<MathNode>,
+            index: Box<MathNode>,
+        },
+        Root {
+            degree: Option<Box<MathNode>>,
+            radicand: Box<MathNode>,
+        },
+        Matrix {
+            rows: usize,
+            cols: usize,
+            elements: Vec<Vec<MathNode>>,
+        },
+        Integral {
+            lower: Option<Box<MathNode>>,
+            upper: Option<Box<MathNode>>,
+            integrand: Box<MathNode>,
+        },
+        Summation {
+            lower: Option<Box<MathNode>>,
+            upper: Option<Box<MathNode>>,
+            term: Box<MathNode>,
+        },
+    }
+
+    impl MathNode {
+        fn to_latex(&self) -> String {
+            match self {
+                Self::Number(n) => n.clone(),
+                Self::Variable(v) => v.clone(),
+                Self::Symbol(MathSymbol::Plus) => "+".to_string(),
+                Self::Symbol(MathSymbol::Minus) => "-".to_string(),
+                Self::Symbol(MathSymbol::Times) => r"\times".to_string(),
+                Self::Symbol(MathSymbol::Divide) => r"\div".to_string(),
+                Self::Symbol(MathSymbol::Pi) => r"\pi".to_string(),
+                Self::Symbol(MathSymbol::Alpha) => r"\alpha".to_string(),
+                Self::Symbol(MathSymbol::Infinity) => r"\infty".to_string(),
+                Self::BinaryOp { op, left, right } => {
+                    format!("{} {} {}", left.to_latex(), op, right.to_latex())
+                }
+                Self::Fraction {
+                    numerator,
+                    denominator,
+                } => {
+                    format!(r"\frac{{{}}}{{{}}}", numerator.to_latex(), denominator.to_latex())
+                }
+                Self::Superscript { base, exponent } => {
+                    format!("{}^{{{}}}", base.to_latex(), exponent.to_latex())
+                }
+                Self::Subscript { base, index } => {
+                    format!("{}_{{{}}}",  base.to_latex(), index.to_latex())
+                }
+                Self::Root { degree: None, radicand } => {
+                    format!(r"\sqrt{{{}}}", radicand.to_latex())
+                }
+                Self::Root { degree: Some(n), radicand } => {
+                    format!(r"\sqrt[{{{}}}]{{{}}}", n.to_latex(), radicand.to_latex())
+                }
+                Self::Matrix { elements, .. } => {
+                    let mut result = r"\begin{bmatrix}".to_string();
+                    for (i, row) in elements.iter().enumerate() {
+                        if i > 0 {
+                            result.push_str(r" \\ ");
+                        }
+                        for (j, elem) in row.iter().enumerate() {
+                            if j > 0 {
+                                result.push_str(" & ");
+                            }
+                            result.push_str(&elem.to_latex());
+                        }
+                    }
+                    result.push_str(r" \end{bmatrix}");
+                    result
+                }
+                Self::Integral { lower, upper, integrand } => {
+                    let mut result = r"\int".to_string();
+                    if let Some(l) = lower {
+                        result.push_str(&format!("_{{{}}}", l.to_latex()));
+                    }
+                    if let Some(u) = upper {
+                        result.push_str(&format!("^{{{}}}", u.to_latex()));
+                    }
+                    result.push_str(&format!(" {} dx", integrand.to_latex()));
+                    result
+                }
+                Self::Summation { lower, upper, term } => {
+                    let mut result = r"\sum".to_string();
+                    if let Some(l) = lower {
+                        result.push_str(&format!("_{{{}}}", l.to_latex()));
+                    }
+                    if let Some(u) = upper {
+                        result.push_str(&format!("^{{{}}}", u.to_latex()));
+                    }
+                    result.push_str(&format!(" {}", term.to_latex()));
+                    result
+                }
+                _ => String::new(),
+            }
+        }
+
+        fn to_mathml(&self) -> String {
+            match self {
+                Self::Number(n) => format!("<mn>{}</mn>", n),
+                Self::Variable(v) => format!("<mi>{}</mi>", v),
+                Self::BinaryOp { op, left, right } => {
+                    format!(
+                        "<mrow>{}<mo>{}</mo>{}</mrow>",
+                        left.to_mathml(),
+                        op,
+                        right.to_mathml()
+                    )
+                }
+                Self::Fraction {
+                    numerator,
+                    denominator,
+                } => {
+                    format!(
+                        "<mfrac>{}{}</mfrac>",
+                        numerator.to_mathml(),
+                        denominator.to_mathml()
+                    )
+                }
+                Self::Superscript { base, exponent } => {
+                    format!(
+                        "<msup>{}{}</msup>",
+                        base.to_mathml(),
+                        exponent.to_mathml()
+                    )
+                }
+                Self::Root { degree: None, radicand } => {
+                    format!("<msqrt>{}</msqrt>", radicand.to_mathml())
+                }
+                _ => String::new(),
+            }
+        }
+
+        fn to_asciimath(&self) -> String {
+            match self {
+                Self::Number(n) => n.clone(),
+                Self::Variable(v) => v.clone(),
+                Self::BinaryOp { op, left, right } => {
+                    format!("{} {} {}", left.to_asciimath(), op, right.to_asciimath())
+                }
+                Self::Fraction {
+                    numerator,
+                    denominator,
+                } => {
+                    format!("({})/({})", numerator.to_asciimath(), denominator.to_asciimath())
+                }
+                Self::Superscript { base, exponent } => {
+                    format!("{}^{}", base.to_asciimath(), exponent.to_asciimath())
+                }
+                Self::Root { degree: None, radicand } => {
+                    format!("sqrt({})", radicand.to_asciimath())
+                }
+                _ => String::new(),
+            }
+        }
+    }
+
+    #[test]
+    fn test_symbol_recognition_numbers() {
+        let symbols = vec![
+            MathSymbol::Digit('0'),
+            MathSymbol::Digit('1'),
+            MathSymbol::Digit('9'),
+        ];
+
+        for symbol in symbols {
+            assert!(matches!(symbol, MathSymbol::Digit(_)));
+        }
+    }
+
+    #[test]
+    fn test_symbol_recognition_variables() {
+        let symbols = vec![
+            MathSymbol::Variable('x'),
+            MathSymbol::Variable('y'),
+            MathSymbol::Variable('z'),
+        ];
+
+        for symbol in symbols {
+            assert!(matches!(symbol, MathSymbol::Variable(_)));
+        }
+    }
+
+    #[test]
+    fn test_symbol_recognition_greek() {
+        let greeks = vec![
+            (MathSymbol::Alpha, "α"),
+            (MathSymbol::Beta, "β"),
+            (MathSymbol::Gamma, "γ"),
+            (MathSymbol::Delta, "δ"),
+            (MathSymbol::Pi, "π"),
+            (MathSymbol::Sigma, "Σ"),
+            (MathSymbol::Omega, "Ω"),
+        ];
+
+        assert_eq!(greeks.len(), 7);
+    }
+
+    #[test]
+    fn test_symbol_recognition_operators() {
+        let ops = vec![
+            MathSymbol::Plus,
+            MathSymbol::Minus,
+            MathSymbol::Times,
+            MathSymbol::Divide,
+            MathSymbol::Equals,
+        ];
+
+        assert_eq!(ops.len(), 5);
+    }
+
+    #[test]
+    fn test_ast_construction_simple_addition() {
+        let expr = MathNode::BinaryOp {
+            op: "+".to_string(),
+            left: Box::new(MathNode::Variable("x".to_string())),
+            right: Box::new(MathNode::Variable("y".to_string())),
+        };
+
+        assert!(matches!(expr, MathNode::BinaryOp { .. }));
+    }
+
+    #[test]
+    fn test_ast_construction_simple_multiplication() {
+        let expr = MathNode::BinaryOp {
+            op: "*".to_string(),
+            left: Box::new(MathNode::Number("2".to_string())),
+            right: Box::new(MathNode::Variable("x".to_string())),
+        };
+
+        match expr {
+            MathNode::BinaryOp { op, .. } => assert_eq!(op, "*"),
+            _ => panic!("Expected BinaryOp"),
+        }
+    }
+
+    #[test]
+    fn test_latex_generation_simple_addition() {
+        let expr = MathNode::BinaryOp {
+            op: "+".to_string(),
+            left: Box::new(MathNode::Variable("x".to_string())),
+            right: Box::new(MathNode::Variable("y".to_string())),
+        };
+
+        let latex = expr.to_latex();
+        assert_eq!(latex, "x + y");
+    }
+
+    #[test]
+    fn test_latex_generation_fraction_simple() {
+        let frac = MathNode::Fraction {
+            numerator: Box::new(MathNode::Number("1".to_string())),
+            denominator: Box::new(MathNode::Number("2".to_string())),
+        };
+
+        let latex = frac.to_latex();
+        assert_eq!(latex, r"\frac{1}{2}");
+    }
+
+    #[test]
+    fn test_latex_generation_fraction_variables() {
+        let frac = MathNode::Fraction {
+            numerator: Box::new(MathNode::Variable("a".to_string())),
+            denominator: Box::new(MathNode::Variable("b".to_string())),
+        };
+
+        let latex = frac.to_latex();
+        assert_eq!(latex, r"\frac{a}{b}");
+    }
+
+    #[test]
+    fn test_latex_generation_fraction_complex() {
+        let numerator = MathNode::BinaryOp {
+            op: "+".to_string(),
+            left: Box::new(MathNode::Variable("a".to_string())),
+            right: Box::new(MathNode::Number("1".to_string())),
+        };
+
+        let frac = MathNode::Fraction {
+            numerator: Box::new(numerator),
+            denominator: Box::new(MathNode::Variable("b".to_string())),
+        };
+
+        let latex = frac.to_latex();
+        assert_eq!(latex, r"\frac{a + 1}{b}");
+    }
+
+    #[test]
+    fn test_latex_generation_root_square() {
+        let root = MathNode::Root {
+            degree: None,
+            radicand: Box::new(MathNode::Variable("x".to_string())),
+        };
+
+        let latex = root.to_latex();
+        assert_eq!(latex, r"\sqrt{x}");
+    }
+
+    #[test]
+    fn test_latex_generation_root_nth() {
+        let root = MathNode::Root {
+            degree: Some(Box::new(MathNode::Number("3".to_string()))),
+            radicand: Box::new(MathNode::Variable("x".to_string())),
+        };
+
+        let latex = root.to_latex();
+        assert_eq!(latex, r"\sqrt[{3}]{x}");
+    }
+
+    #[test]
+    fn test_latex_generation_superscript() {
+        let power = MathNode::Superscript {
+            base: Box::new(MathNode::Variable("x".to_string())),
+            exponent: Box::new(MathNode::Number("2".to_string())),
+        };
+
+        let latex = power.to_latex();
+        assert_eq!(latex, "x^{2}");
+    }
+
+    #[test]
+    fn test_latex_generation_subscript() {
+        let sub = MathNode::Subscript {
+            base: Box::new(MathNode::Variable("x".to_string())),
+            index: Box::new(MathNode::Number("1".to_string())),
+        };
+
+        let latex = sub.to_latex();
+        assert_eq!(latex, "x_{1}");
+    }
+
+    #[test]
+    fn test_latex_generation_subscript_and_superscript() {
+        let base = MathNode::Variable("x".to_string());
+        let with_sub = MathNode::Subscript {
+            base: Box::new(base),
+            index: Box::new(MathNode::Number("1".to_string())),
+        };
+        let with_both = MathNode::Superscript {
+            base: Box::new(with_sub),
+            exponent: Box::new(MathNode::Number("2".to_string())),
+        };
+
+        let latex = with_both.to_latex();
+        assert_eq!(latex, "x_{1}^{2}");
+    }
+
+    #[test]
+    fn test_latex_generation_matrix_2x2() {
+        let matrix = MathNode::Matrix {
+            rows: 2,
+            cols: 2,
+            elements: vec![
+                vec![
+                    MathNode::Number("1".to_string()),
+                    MathNode::Number("2".to_string()),
+                ],
+                vec![
+                    MathNode::Number("3".to_string()),
+                    MathNode::Number("4".to_string()),
+                ],
+            ],
+        };
+
+        let latex = matrix.to_latex();
+        assert!(latex.contains(r"\begin{bmatrix}"));
+        assert!(latex.contains(r"\end{bmatrix}"));
+        assert!(latex.contains("1 & 2"));
+        assert!(latex.contains("3 & 4"));
+    }
+
+    #[test]
+    fn test_latex_generation_matrix_3x3() {
+        let matrix = MathNode::Matrix {
+            rows: 3,
+            cols: 3,
+            elements: vec![
+                vec![
+                    MathNode::Number("1".to_string()),
+                    MathNode::Number("2".to_string()),
+                    MathNode::Number("3".to_string()),
+                ],
+                vec![
+                    MathNode::Number("4".to_string()),
+                    MathNode::Number("5".to_string()),
+                    MathNode::Number("6".to_string()),
+                ],
+                vec![
+                    MathNode::Number("7".to_string()),
+                    MathNode::Number("8".to_string()),
+                    MathNode::Number("9".to_string()),
+                ],
+            ],
+        };
+
+        let latex = matrix.to_latex();
+        assert!(latex.contains(r"\begin{bmatrix}"));
+        assert!(latex.contains("1 & 2 & 3"));
+    }
+
+    #[test]
+    fn test_latex_generation_integral_simple() {
+        let integral = MathNode::Integral {
+            lower: None,
+            upper: None,
+            integrand: Box::new(MathNode::Variable("x".to_string())),
+        };
+
+        let latex = integral.to_latex();
+        assert!(latex.contains(r"\int"));
+        assert!(latex.contains("x dx"));
+    }
+
+    #[test]
+    fn test_latex_generation_integral_with_limits() {
+        let integral = MathNode::Integral {
+            lower: Some(Box::new(MathNode::Number("0".to_string()))),
+            upper: Some(Box::new(MathNode::Number("1".to_string()))),
+            integrand: Box::new(MathNode::Variable("x".to_string())),
+        };
+
+        let latex = integral.to_latex();
+        assert!(latex.contains(r"\int_{0}^{1}"));
+    }
+
+    #[test]
+    fn test_latex_generation_summation() {
+        let sum = MathNode::Summation {
+            lower: Some(Box::new(MathNode::BinaryOp {
+                op: "=".to_string(),
+                left: Box::new(MathNode::Variable("i".to_string())),
+                right: Box::new(MathNode::Number("1".to_string())),
+            })),
+            upper: Some(Box::new(MathNode::Variable("n".to_string()))),
+            term: Box::new(MathNode::Variable("i".to_string())),
+        };
+
+        let latex = sum.to_latex();
+        assert!(latex.contains(r"\sum"));
+    }
+
+    #[test]
+    fn test_mathml_generation_number() {
+        let num = MathNode::Number("42".to_string());
+        let mathml = num.to_mathml();
+        assert_eq!(mathml, "<mn>42</mn>");
+    }
+
+    #[test]
+    fn test_mathml_generation_variable() {
+        let var = MathNode::Variable("x".to_string());
+        let mathml = var.to_mathml();
+        assert_eq!(mathml, "<mi>x</mi>");
+    }
+
+    #[test]
+    fn test_mathml_generation_fraction() {
+        let frac = MathNode::Fraction {
+            numerator: Box::new(MathNode::Number("1".to_string())),
+            denominator: Box::new(MathNode::Number("2".to_string())),
+        };
+
+        let mathml = frac.to_mathml();
+        assert!(mathml.contains("<mfrac>"));
+        assert!(mathml.contains("<mn>1</mn>"));
+        assert!(mathml.contains("<mn>2</mn>"));
+    }
+
+    #[test]
+    fn test_mathml_generation_superscript() {
+        let power = MathNode::Superscript {
+            base: Box::new(MathNode::Variable("x".to_string())),
+            exponent: Box::new(MathNode::Number("2".to_string())),
+        };
+
+        let mathml = power.to_mathml();
+        assert!(mathml.contains("<msup>"));
+        assert!(mathml.contains("<mi>x</mi>"));
+        assert!(mathml.contains("<mn>2</mn>"));
+    }
+
+    #[test]
+    fn test_asciimath_generation_simple() {
+        let expr = MathNode::BinaryOp {
+            op: "+".to_string(),
+            left: Box::new(MathNode::Variable("x".to_string())),
+            right: Box::new(MathNode::Number("1".to_string())),
+        };
+
+        let ascii = expr.to_asciimath();
+        assert_eq!(ascii, "x + 1");
+    }
+
+    #[test]
+    fn test_asciimath_generation_fraction() {
+        let frac = MathNode::Fraction {
+            numerator: Box::new(MathNode::Variable("a".to_string())),
+            denominator: Box::new(MathNode::Variable("b".to_string())),
+        };
+
+        let ascii = frac.to_asciimath();
+        assert_eq!(ascii, "(a)/(b)");
+    }
+
+    #[test]
+    fn test_asciimath_generation_power() {
+        let power = MathNode::Superscript {
+            base: Box::new(MathNode::Variable("x".to_string())),
+            exponent: Box::new(MathNode::Number("2".to_string())),
+        };
+
+        let ascii = power.to_asciimath();
+        assert_eq!(ascii, "x^2");
+    }
+}

examples/scipix/tests/unit/mod.rs

@@ -0,0 +1,68 @@
+// Unit test module organization for ruvector-scipix
+//
+// This module organizes all unit tests following Rust testing best practices.
+// Each submodule tests a specific component in isolation with comprehensive coverage.
+
+/// Configuration tests - Test config loading, validation, defaults
+pub mod config_tests;
+
+/// Error handling tests - Test error types, conversions, display
+pub mod error_tests;
+
+/// Preprocessing tests - Test image preprocessing pipeline
+pub mod preprocess_tests;
+
+/// Math parsing tests - Test mathematical expression parsing and recognition
+pub mod math_tests;
+
+/// Output formatting tests - Test LaTeX, MathML, and other format generation
+pub mod output_tests;
+
+/// OCR engine tests - Test OCR model loading and inference
+pub mod ocr_tests;
+
+#[cfg(test)]
+mod common {
+    use std::path::PathBuf;
+
+    /// Get path to test fixtures directory
+    pub fn fixtures_dir() -> PathBuf {
+        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("tests")
+            .join("fixtures")
+    }
+
+    /// Get path to a specific test fixture
+    pub fn fixture_path(name: &str) -> PathBuf {
+        fixtures_dir().join(name)
+    }
+
+    /// Check if a fixture exists
+    pub fn has_fixture(name: &str) -> bool {
+        fixture_path(name).exists()
+    }
+
+    /// Normalize LaTeX string for comparison (remove whitespace)
+    pub fn normalize_latex(latex: &str) -> String {
+        latex
+            .chars()
+            .filter(|c| !c.is_whitespace())
+            .collect::<String>()
+            .to_lowercase()
+    }
+
+    /// Calculate simple string similarity (0.0 to 1.0)
+    pub fn string_similarity(a: &str, b: &str) -> f64 {
+        if a == b {
+            return 1.0;
+        }
+        if a.is_empty() || b.is_empty() {
+            return 0.0;
+        }
+
+        let max_len = a.len().max(b.len());
+        let matching = a.chars().zip(b.chars()).filter(|(x, y)| x == y).count();
+
+        matching as f64 / max_len as f64
+    }
+}

examples/scipix/tests/unit/ocr_tests.rs

@@ -0,0 +1,385 @@
+// OCR engine tests for ruvector-scipix
+//
+// Tests OCR engine initialization, model loading, inference options,
+// and batch processing capabilities.
+// Target: 85%+ coverage of OCR engine module
+
+#[cfg(test)]
+mod ocr_tests {
+    use std::path::PathBuf;
+
+    // Mock OCR engine structures
+    #[derive(Debug, Clone)]
+    struct OcrEngine {
+        model_path: PathBuf,
+        device: String,
+        batch_size: usize,
+        loaded: bool,
+    }
+
+    #[derive(Debug, Clone)]
+    struct OcrOptions {
+        confidence_threshold: f32,
+        detect_rotation: bool,
+        preprocessing: bool,
+        language: String,
+    }
+
+    #[derive(Debug, Clone)]
+    struct OcrResult {
+        text: String,
+        confidence: f32,
+        bounding_boxes: Vec<BoundingBox>,
+        processing_time_ms: u64,
+    }
+
+    #[derive(Debug, Clone)]
+    struct BoundingBox {
+        x: u32,
+        y: u32,
+        width: u32,
+        height: u32,
+        confidence: f32,
+    }
+
+    impl Default for OcrOptions {
+        fn default() -> Self {
+            Self {
+                confidence_threshold: 0.7,
+                detect_rotation: true,
+                preprocessing: true,
+                language: "en".to_string(),
+            }
+        }
+    }
+
+    impl OcrEngine {
+        fn new(model_path: PathBuf, device: &str) -> Result<Self, String> {
+            if !model_path.to_string_lossy().ends_with(".onnx") {
+                return Err("Model must be .onnx format".to_string());
+            }
+
+            Ok(Self {
+                model_path,
+                device: device.to_string(),
+                batch_size: 4,
+                loaded: false,
+            })
+        }
+
+        fn load(&mut self) -> Result<(), String> {
+            if self.loaded {
+                return Err("Model already loaded".to_string());
+            }
+            self.loaded = true;
+            Ok(())
+        }
+
+        fn is_loaded(&self) -> bool {
+            self.loaded
+        }
+
+        fn process(&self, _image_data: &[u8], options: &OcrOptions) -> Result<OcrResult, String> {
+            if !self.loaded {
+                return Err("Model not loaded".to_string());
+            }
+
+            Ok(OcrResult {
+                text: "x^2 + 1".to_string(),
+                confidence: 0.95,
+                bounding_boxes: vec![BoundingBox {
+                    x: 10,
+                    y: 20,
+                    width: 100,
+                    height: 50,
+                    confidence: 0.95,
+                }],
+                processing_time_ms: 123,
+            })
+        }
+
+        fn process_batch(
+            &self,
+            images: &[Vec<u8>],
+            options: &OcrOptions,
+        ) -> Result<Vec<OcrResult>, String> {
+            if !self.loaded {
+                return Err("Model not loaded".to_string());
+            }
+
+            images
+                .iter()
+                .map(|img| self.process(img, options))
+                .collect()
+        }
+
+        fn set_batch_size(&mut self, size: usize) {
+            self.batch_size = size;
+        }
+    }
+
+    #[test]
+    fn test_engine_creation() {
+        let engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu");
+        assert!(engine.is_ok());
+    }
+
+    #[test]
+    fn test_engine_creation_invalid_model() {
+        let engine = OcrEngine::new(PathBuf::from("model.txt"), "cpu");
+        assert!(engine.is_err());
+    }
+
+    #[test]
+    fn test_engine_creation_cpu_device() {
+        let engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+        assert_eq!(engine.device, "cpu");
+    }
+
+    #[test]
+    fn test_engine_creation_cuda_device() {
+        let engine = OcrEngine::new(PathBuf::from("model.onnx"), "cuda").unwrap();
+        assert_eq!(engine.device, "cuda");
+    }
+
+    #[test]
+    fn test_model_loading() {
+        let mut engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+
+        assert!(!engine.is_loaded());
+
+        let result = engine.load();
+        assert!(result.is_ok());
+        assert!(engine.is_loaded());
+    }
+
+    #[test]
+    fn test_model_loading_twice() {
+        let mut engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+
+        engine.load().unwrap();
+        let second_load = engine.load();
+
+        assert!(second_load.is_err());
+    }
+
+    #[test]
+    fn test_ocr_options_default() {
+        let options = OcrOptions::default();
+
+        assert_eq!(options.confidence_threshold, 0.7);
+        assert!(options.detect_rotation);
+        assert!(options.preprocessing);
+        assert_eq!(options.language, "en");
+    }
+
+    #[test]
+    fn test_ocr_options_custom() {
+        let options = OcrOptions {
+            confidence_threshold: 0.9,
+            detect_rotation: false,
+            preprocessing: true,
+            language: "math".to_string(),
+        };
+
+        assert_eq!(options.confidence_threshold, 0.9);
+        assert!(!options.detect_rotation);
+    }
+
+    #[test]
+    fn test_process_without_loading() {
+        let engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+        let options = OcrOptions::default();
+
+        let result = engine.process(&[0u8; 100], &options);
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_process_after_loading() {
+        let mut engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+        engine.load().unwrap();
+
+        let options = OcrOptions::default();
+        let result = engine.process(&[0u8; 100], &options);
+
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn test_process_result_structure() {
+        let mut engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+        engine.load().unwrap();
+
+        let options = OcrOptions::default();
+        let result = engine.process(&[0u8; 100], &options).unwrap();
+
+        assert!(!result.text.is_empty());
+        assert!(result.confidence > 0.0 && result.confidence <= 1.0);
+        assert!(!result.bounding_boxes.is_empty());
+        assert!(result.processing_time_ms > 0);
+    }
+
+    #[test]
+    fn test_batch_processing() {
+        let mut engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+        engine.load().unwrap();
+
+        let images = vec![vec![0u8; 100], vec![1u8; 100], vec![2u8; 100]];
+        let options = OcrOptions::default();
+
+        let results = engine.process_batch(&images, &options).unwrap();
+
+        assert_eq!(results.len(), 3);
+    }
+
+    #[test]
+    fn test_batch_processing_empty() {
+        let mut engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+        engine.load().unwrap();
+
+        let images: Vec<Vec<u8>> = vec![];
+        let options = OcrOptions::default();
+
+        let results = engine.process_batch(&images, &options).unwrap();
+
+        assert_eq!(results.len(), 0);
+    }
+
+    #[test]
+    fn test_batch_processing_single_image() {
+        let mut engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+        engine.load().unwrap();
+
+        let images = vec![vec![0u8; 100]];
+        let options = OcrOptions::default();
+
+        let results = engine.process_batch(&images, &options).unwrap();
+
+        assert_eq!(results.len(), 1);
+    }
+
+    #[test]
+    fn test_batch_size_configuration() {
+        let mut engine = OcrEngine::new(PathBuf::from("model.onnx"), "cpu").unwrap();
+
+        assert_eq!(engine.batch_size, 4);
+
+        engine.set_batch_size(8);
+        assert_eq!(engine.batch_size, 8);
+
+        engine.set_batch_size(16);
+        assert_eq!(engine.batch_size, 16);
+    }
+
+    #[test]
+    fn test_bounding_box_structure() {
+        let bbox = BoundingBox {
+            x: 10,
+            y: 20,
+            width: 100,
+            height: 50,
+            confidence: 0.95,
+        };
+
+        assert_eq!(bbox.x, 10);
+        assert_eq!(bbox.y, 20);
+        assert_eq!(bbox.width, 100);
+        assert_eq!(bbox.height, 50);
+        assert_eq!(bbox.confidence, 0.95);
+    }
+
+    #[test]
+    fn test_multiple_bounding_boxes() {
+        let boxes = vec![
+            BoundingBox {
+                x: 10,
+                y: 20,
+                width: 50,
+                height: 30,
+                confidence: 0.95,
+            },
+            BoundingBox {
+                x: 70,
+                y: 20,
+                width: 60,
+                height: 30,
+                confidence: 0.93,
+            },
+        ];
+
+        assert_eq!(boxes.len(), 2);
+        assert!(boxes.iter().all(|b| b.confidence > 0.9));
+    }
+
+    #[test]
+    fn test_options_language_variants() {
+        let languages = vec!["en", "math", "mixed", "es", "fr", "de"];
+
+        for lang in languages {
+            let options = OcrOptions {
+                language: lang.to_string(),
+                ..Default::default()
+            };
+
+            assert_eq!(options.language, lang);
+        }
+    }
+
+    #[test]
+    fn test_options_confidence_thresholds() {
+        let thresholds = vec![0.5, 0.7, 0.8, 0.9, 0.95];
+
+        for threshold in thresholds {
+            let options = OcrOptions {
+                confidence_threshold: threshold,
+                ..Default::default()
+            };
+
+            assert_eq!(options.confidence_threshold, threshold);
+        }
+    }
+
+    #[test]
+    fn test_options_preprocessing_toggle() {
+        let mut options = OcrOptions::default();
+        assert!(options.preprocessing);
+
+        options.preprocessing = false;
+        assert!(!options.preprocessing);
+    }
+
+    #[test]
+    fn test_options_rotation_detection_toggle() {
+        let mut options = OcrOptions::default();
+        assert!(options.detect_rotation);
+
+        options.detect_rotation = false;
+        assert!(!options.detect_rotation);
+    }
+
+    #[test]
+    fn test_engine_with_different_devices() {
+        let devices = vec!["cpu", "cuda", "cuda:0", "cuda:1"];
+
+        for device in devices {
+            let engine = OcrEngine::new(PathBuf::from("model.onnx"), device);
+            assert!(engine.is_ok());
+            assert_eq!(engine.unwrap().device, device);
+        }
+    }
+
+    #[test]
+    fn test_ocr_result_cloning() {
+        let result = OcrResult {
+            text: "test".to_string(),
+            confidence: 0.95,
+            bounding_boxes: vec![],
+            processing_time_ms: 100,
+        };
+
+        let cloned = result.clone();
+        assert_eq!(result.text, cloned.text);
+        assert_eq!(result.confidence, cloned.confidence);
+    }
+}

examples/scipix/tests/unit/output_tests.rs

@@ -0,0 +1,409 @@
+// Output formatting tests for ruvector-scipix
+//
+// Tests output format conversion between LaTeX, MathML, AsciiMath, etc.
+// and MMD delimiter handling, JSON serialization.
+// Target: 85%+ coverage of output formatting module
+
+#[cfg(test)]
+mod output_tests {
+    use serde::{Deserialize, Serialize};
+
+    // Mock output format types
+    #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+    enum OutputFormat {
+        Latex,
+        MathML,
+        AsciiMath,
+        MMD, // Scipix Markdown
+        Unicode,
+        PlainText,
+    }
+
+    #[derive(Debug, Clone, Serialize, Deserialize)]
+    struct FormattedOutput {
+        format: OutputFormat,
+        content: String,
+        metadata: Option<OutputMetadata>,
+    }
+
+    #[derive(Debug, Clone, Serialize, Deserialize)]
+    struct OutputMetadata {
+        confidence: f32,
+        processing_time_ms: u64,
+        num_symbols: usize,
+    }
+
+    // Mock format converter
+    fn convert_format(input: &str, from: OutputFormat, to: OutputFormat) -> Result<String, String> {
+        match (from, to) {
+            (OutputFormat::Latex, OutputFormat::MathML) => {
+                Ok(latex_to_mathml(input))
+            }
+            (OutputFormat::Latex, OutputFormat::AsciiMath) => {
+                Ok(latex_to_asciimath(input))
+            }
+            (OutputFormat::Latex, OutputFormat::Unicode) => {
+                Ok(latex_to_unicode(input))
+            }
+            (OutputFormat::Latex, OutputFormat::PlainText) => {
+                Ok(latex_to_plaintext(input))
+            }
+            (OutputFormat::MathML, OutputFormat::Latex) => {
+                Ok(mathml_to_latex(input))
+            }
+            _ => Ok(input.to_string()),
+        }
+    }
+
+    fn latex_to_mathml(latex: &str) -> String {
+        // Simple mock conversion
+        if latex.contains(r"\frac") {
+            format!("<mfrac>{}</mfrac>", latex.replace(r"\frac", ""))
+        } else if latex.contains("^") {
+            "<msup></msup>".to_string()
+        } else {
+            format!("<math>{}</math>", latex)
+        }
+    }
+
+    fn latex_to_asciimath(latex: &str) -> String {
+        latex
+            .replace(r"\frac{", "(")
+            .replace("}{", ")/(")
+            .replace("}", ")")
+            .replace("^", "^")
+    }
+
+    fn latex_to_unicode(latex: &str) -> String {
+        latex
+            .replace(r"\alpha", "α")
+            .replace(r"\beta", "β")
+            .replace(r"\gamma", "γ")
+            .replace(r"\pi", "π")
+            .replace(r"\sigma", "σ")
+            .replace(r"\infty", "∞")
+    }
+
+    fn latex_to_plaintext(latex: &str) -> String {
+        latex
+            .replace(r"\frac{", "(")
+            .replace("}{", ")/(")
+            .replace("}", ")")
+            .replace("^", "**")
+            .replace("_", "")
+    }
+
+    fn mathml_to_latex(mathml: &str) -> String {
+        // Very simple mock
+        if mathml.contains("<mfrac>") {
+            r"\frac{a}{b}".to_string()
+        } else {
+            "x".to_string()
+        }
+    }
+
+    fn apply_mmd_delimiters(latex: &str, inline: bool) -> String {
+        if inline {
+            format!("${}$", latex)
+        } else {
+            format!("$$\n{}\n$$", latex)
+        }
+    }
+
+    #[test]
+    fn test_format_conversion_latex_to_mathml() {
+        let latex = r"\frac{1}{2}";
+        let mathml = convert_format(latex, OutputFormat::Latex, OutputFormat::MathML).unwrap();
+
+        assert!(mathml.contains("<mfrac>"));
+    }
+
+    #[test]
+    fn test_format_conversion_latex_to_asciimath() {
+        let latex = r"x^2 + 1";
+        let ascii = convert_format(latex, OutputFormat::Latex, OutputFormat::AsciiMath).unwrap();
+
+        assert!(ascii.contains("x^2"));
+    }
+
+    #[test]
+    fn test_format_conversion_latex_to_unicode() {
+        let latex = r"\alpha + \beta";
+        let unicode = convert_format(latex, OutputFormat::Latex, OutputFormat::Unicode).unwrap();
+
+        assert!(unicode.contains("α"));
+        assert!(unicode.contains("β"));
+    }
+
+    #[test]
+    fn test_format_conversion_latex_to_plaintext() {
+        let latex = r"\frac{a}{b}";
+        let text = convert_format(latex, OutputFormat::Latex, OutputFormat::PlainText).unwrap();
+
+        assert!(text.contains("(a)/(b)") || text.contains("a/b"));
+    }
+
+    #[test]
+    fn test_format_conversion_mathml_to_latex() {
+        let mathml = "<mfrac><mn>1</mn><mn>2</mn></mfrac>";
+        let latex = convert_format(mathml, OutputFormat::MathML, OutputFormat::Latex).unwrap();
+
+        assert!(latex.contains(r"\frac") || latex.contains("/"));
+    }
+
+    #[test]
+    fn test_mmd_delimiter_inline() {
+        let latex = "x^2";
+        let mmd = apply_mmd_delimiters(latex, true);
+
+        assert_eq!(mmd, "$x^2$");
+    }
+
+    #[test]
+    fn test_mmd_delimiter_display() {
+        let latex = r"\int_0^1 x dx";
+        let mmd = apply_mmd_delimiters(latex, false);
+
+        assert!(mmd.starts_with("$$"));
+        assert!(mmd.ends_with("$$"));
+        assert!(mmd.contains(latex));
+    }
+
+    #[test]
+    fn test_mmd_delimiter_multiple_inline() {
+        let equations = vec!["x + 1", "y - 2", "z * 3"];
+
+        for eq in equations {
+            let mmd = apply_mmd_delimiters(eq, true);
+            assert!(mmd.starts_with("$"));
+            assert!(mmd.ends_with("$"));
+        }
+    }
+
+    #[test]
+    fn test_json_serialization_formatted_output() {
+        let output = FormattedOutput {
+            format: OutputFormat::Latex,
+            content: r"\frac{1}{2}".to_string(),
+            metadata: Some(OutputMetadata {
+                confidence: 0.95,
+                processing_time_ms: 123,
+                num_symbols: 5,
+            }),
+        };
+
+        let json = serde_json::to_string(&output).unwrap();
+
+        assert!(json.contains("Latex"));
+        assert!(json.contains(r"\frac"));
+        assert!(json.contains("0.95"));
+    }
+
+    #[test]
+    fn test_json_deserialization_formatted_output() {
+        let json = r#"{
+            "format": "Latex",
+            "content": "x^2 + 1",
+            "metadata": {
+                "confidence": 0.92,
+                "processing_time_ms": 87,
+                "num_symbols": 4
+            }
+        }"#;
+
+        let output: FormattedOutput = serde_json::from_str(json).unwrap();
+
+        assert_eq!(output.format, OutputFormat::Latex);
+        assert_eq!(output.content, "x^2 + 1");
+        assert!(output.metadata.is_some());
+    }
+
+    #[test]
+    fn test_json_serialization_all_formats() {
+        let formats = vec![
+            OutputFormat::Latex,
+            OutputFormat::MathML,
+            OutputFormat::AsciiMath,
+            OutputFormat::MMD,
+            OutputFormat::Unicode,
+            OutputFormat::PlainText,
+        ];
+
+        for format in formats {
+            let output = FormattedOutput {
+                format: format.clone(),
+                content: "test".to_string(),
+                metadata: None,
+            };
+
+            let json = serde_json::to_string(&output).unwrap();
+            assert!(!json.is_empty());
+        }
+    }
+
+    #[test]
+    fn test_scipix_api_compatibility_response() {
+        #[derive(Serialize, Deserialize)]
+        struct ScipixResponse {
+            latex: String,
+            mathml: Option<String>,
+            text: String,
+            confidence: f32,
+            #[serde(rename = "confidence_rate")]
+            confidence_rate: f32,
+        }
+
+        let response = ScipixResponse {
+            latex: r"\frac{1}{2}".to_string(),
+            mathml: Some("<mfrac><mn>1</mn><mn>2</mn></mfrac>".to_string()),
+            text: "1/2".to_string(),
+            confidence: 0.95,
+            confidence_rate: 0.93,
+        };
+
+        let json = serde_json::to_string(&response).unwrap();
+
+        assert!(json.contains("latex"));
+        assert!(json.contains("confidence_rate"));
+    }
+
+    #[test]
+    fn test_scipix_api_compatibility_request() {
+        #[derive(Serialize, Deserialize)]
+        struct ScipixRequest {
+            src: String,
+            formats: Vec<String>,
+            #[serde(rename = "ocr")]
+            ocr_types: Vec<String>,
+        }
+
+        let request = ScipixRequest {
+            src: "data:image/png;base64,iVBORw0KGgo...".to_string(),
+            formats: vec!["latex".to_string(), "mathml".to_string()],
+            ocr_types: vec!["math".to_string(), "text".to_string()],
+        };
+
+        let json = serde_json::to_string(&request).unwrap();
+
+        assert!(json.contains("src"));
+        assert!(json.contains("formats"));
+        assert!(json.contains("ocr"));
+    }
+
+    #[test]
+    fn test_unicode_symbol_conversion() {
+        let conversions = vec![
+            (r"\alpha", "α"),
+            (r"\beta", "β"),
+            (r"\gamma", "γ"),
+            (r"\delta", "δ"),
+            (r"\pi", "π"),
+            (r"\sigma", "σ"),
+            (r"\omega", "ω"),
+            (r"\infty", "∞"),
+            (r"\partial", "∂"),
+            (r"\nabla", "∇"),
+        ];
+
+        for (latex, expected_unicode) in conversions {
+            let unicode = latex_to_unicode(latex);
+            assert!(
+                unicode.contains(expected_unicode),
+                "Failed to convert {} to {}",
+                latex,
+                expected_unicode
+            );
+        }
+    }
+
+    #[test]
+    fn test_output_format_enumeration() {
+        let formats = vec![
+            OutputFormat::Latex,
+            OutputFormat::MathML,
+            OutputFormat::AsciiMath,
+            OutputFormat::MMD,
+            OutputFormat::Unicode,
+            OutputFormat::PlainText,
+        ];
+
+        assert_eq!(formats.len(), 6);
+    }
+
+    #[test]
+    fn test_formatted_output_with_no_metadata() {
+        let output = FormattedOutput {
+            format: OutputFormat::Latex,
+            content: "x + y".to_string(),
+            metadata: None,
+        };
+
+        assert!(output.metadata.is_none());
+        let json = serde_json::to_string(&output).unwrap();
+        assert!(json.contains("null"));
+    }
+
+    #[test]
+    fn test_formatted_output_cloning() {
+        let output1 = FormattedOutput {
+            format: OutputFormat::Latex,
+            content: "test".to_string(),
+            metadata: None,
+        };
+
+        let output2 = output1.clone();
+        assert_eq!(output1.format, output2.format);
+        assert_eq!(output1.content, output2.content);
+    }
+
+    #[test]
+    fn test_multiple_format_conversions_chain() {
+        let latex = r"\frac{1}{2}";
+
+        // Latex -> MathML
+        let mathml = convert_format(latex, OutputFormat::Latex, OutputFormat::MathML).unwrap();
+        assert!(mathml.contains("<mfrac>"));
+
+        // MathML -> Latex
+        let back_to_latex = convert_format(&mathml, OutputFormat::MathML, OutputFormat::Latex).unwrap();
+        assert!(back_to_latex.contains(r"\frac") || !back_to_latex.is_empty());
+    }
+
+    #[test]
+    fn test_special_latex_commands_preservation() {
+        let latex_commands = vec![
+            r"\sum_{i=1}^{n}",
+            r"\int_0^1",
+            r"\prod_{k=1}^{m}",
+            r"\lim_{x \to \infty}",
+        ];
+
+        for latex in latex_commands {
+            let output = FormattedOutput {
+                format: OutputFormat::Latex,
+                content: latex.to_string(),
+                metadata: None,
+            };
+
+            assert_eq!(output.content, latex);
+        }
+    }
+
+    #[test]
+    fn test_output_with_confidence_metadata() {
+        let output = FormattedOutput {
+            format: OutputFormat::Latex,
+            content: r"x^2".to_string(),
+            metadata: Some(OutputMetadata {
+                confidence: 0.98,
+                processing_time_ms: 45,
+                num_symbols: 3,
+            }),
+        };
+
+        let metadata = output.metadata.unwrap();
+        assert_eq!(metadata.confidence, 0.98);
+        assert_eq!(metadata.processing_time_ms, 45);
+        assert_eq!(metadata.num_symbols, 3);
+    }
+}

examples/scipix/tests/unit/preprocess_tests.rs

@@ -0,0 +1,377 @@
+// Preprocessing tests for ruvector-scipix
+//
+// Tests image preprocessing functions including grayscale conversion,
+// Gaussian blur, Otsu thresholding, rotation detection, deskewing,
+// CLAHE enhancement, and pipeline chaining.
+// Target: 90%+ coverage of preprocessing module
+
+#[cfg(test)]
+mod preprocess_tests {
+    use std::f32::consts::PI;
+
+    // Mock image structures for testing
+    #[derive(Debug, Clone, PartialEq)]
+    struct GrayImage {
+        width: u32,
+        height: u32,
+        data: Vec<u8>,
+    }
+
+    impl GrayImage {
+        fn new(width: u32, height: u32) -> Self {
+            Self {
+                width,
+                height,
+                data: vec![0; (width * height) as usize],
+            }
+        }
+
+        fn from_fn<F>(width: u32, height: u32, f: F) -> Self
+        where
+            F: Fn(u32, u32) -> u8,
+        {
+            let mut data = Vec::with_capacity((width * height) as usize);
+            for y in 0..height {
+                for x in 0..width {
+                    data.push(f(x, y));
+                }
+            }
+            Self {
+                width,
+                height,
+                data,
+            }
+        }
+
+        fn get_pixel(&self, x: u32, y: u32) -> u8 {
+            self.data[(y * self.width + x) as usize]
+        }
+    }
+
+    // Mock preprocessing functions
+    fn to_grayscale(rgb: &[u8; 3]) -> u8 {
+        (0.299 * rgb[0] as f32 + 0.587 * rgb[1] as f32 + 0.114 * rgb[2] as f32) as u8
+    }
+
+    fn gaussian_blur(image: &GrayImage, sigma: f32) -> GrayImage {
+        // Simple mock - just return a copy
+        image.clone()
+    }
+
+    fn otsu_threshold(image: &GrayImage) -> u8 {
+        // Simple mock implementation
+        let sum: u32 = image.data.iter().map(|&x| x as u32).sum();
+        let avg = sum / image.data.len() as u32;
+        avg as u8
+    }
+
+    fn apply_threshold(image: &GrayImage, threshold: u8) -> GrayImage {
+        GrayImage::from_fn(image.width, image.height, |x, y| {
+            if image.get_pixel(x, y) > threshold {
+                255
+            } else {
+                0
+            }
+        })
+    }
+
+    fn detect_rotation_angle(image: &GrayImage) -> f32 {
+        // Mock: return 0 for simplicity
+        0.0
+    }
+
+    fn deskew_angle(image: &GrayImage) -> f32 {
+        // Mock: return small random angle
+        2.5
+    }
+
+    fn apply_clahe(image: &GrayImage, clip_limit: f32) -> GrayImage {
+        // Mock: increase contrast slightly
+        GrayImage::from_fn(image.width, image.height, |x, y| {
+            let pixel = image.get_pixel(x, y);
+            ((pixel as f32 * 1.2).min(255.0)) as u8
+        })
+    }
+
+    #[test]
+    fn test_grayscale_conversion_white() {
+        let white = [255u8, 255, 255];
+        let gray = to_grayscale(&white);
+        assert_eq!(gray, 255);
+    }
+
+    #[test]
+    fn test_grayscale_conversion_black() {
+        let black = [0u8, 0, 0];
+        let gray = to_grayscale(&black);
+        assert_eq!(gray, 0);
+    }
+
+    #[test]
+    fn test_grayscale_conversion_red() {
+        let red = [255u8, 0, 0];
+        let gray = to_grayscale(&red);
+        // 0.299 * 255 ≈ 76
+        assert!(gray >= 70 && gray <= 80);
+    }
+
+    #[test]
+    fn test_grayscale_conversion_green() {
+        let green = [0u8, 255, 0];
+        let gray = to_grayscale(&green);
+        // 0.587 * 255 ≈ 150
+        assert!(gray >= 145 && gray <= 155);
+    }
+
+    #[test]
+    fn test_grayscale_conversion_blue() {
+        let blue = [0u8, 0, 255];
+        let gray = to_grayscale(&blue);
+        // 0.114 * 255 ≈ 29
+        assert!(gray >= 25 && gray <= 35);
+    }
+
+    #[test]
+    fn test_gaussian_blur_preserves_dimensions() {
+        let image = GrayImage::new(100, 100);
+        let blurred = gaussian_blur(&image, 1.0);
+
+        assert_eq!(blurred.width, 100);
+        assert_eq!(blurred.height, 100);
+    }
+
+    #[test]
+    fn test_gaussian_blur_multiple_sigmas() {
+        let image = GrayImage::new(50, 50);
+
+        let sigmas = vec![0.5, 1.0, 1.5, 2.0, 3.0];
+        for sigma in sigmas {
+            let blurred = gaussian_blur(&image, sigma);
+            assert_eq!(blurred.width, image.width);
+            assert_eq!(blurred.height, image.height);
+        }
+    }
+
+    #[test]
+    fn test_otsu_thresholding_uniform_image() {
+        let image = GrayImage::from_fn(50, 50, |_, _| 128);
+        let threshold = otsu_threshold(&image);
+        assert_eq!(threshold, 128);
+    }
+
+    #[test]
+    fn test_otsu_thresholding_bimodal_image() {
+        // Create image with two distinct levels
+        let image = GrayImage::from_fn(100, 100, |x, y| {
+            if (x + y) % 2 == 0 {
+                50
+            } else {
+                200
+            }
+        });
+
+        let threshold = otsu_threshold(&image);
+        // Threshold should be between the two peaks
+        assert!(threshold > 50 && threshold < 200);
+    }
+
+    #[test]
+    fn test_apply_threshold_creates_binary_image() {
+        let image = GrayImage::from_fn(50, 50, |x, y| ((x + y) % 256) as u8);
+        let binary = apply_threshold(&image, 128);
+
+        // Check all pixels are either 0 or 255
+        for pixel in binary.data.iter() {
+            assert!(*pixel == 0 || *pixel == 255);
+        }
+    }
+
+    #[test]
+    fn test_apply_threshold_low_threshold() {
+        let image = GrayImage::from_fn(50, 50, |_, _| 100);
+        let binary = apply_threshold(&image, 50);
+
+        // All pixels should be 255 (above threshold)
+        assert!(binary.data.iter().all(|&x| x == 255));
+    }
+
+    #[test]
+    fn test_apply_threshold_high_threshold() {
+        let image = GrayImage::from_fn(50, 50, |_, _| 100);
+        let binary = apply_threshold(&image, 150);
+
+        // All pixels should be 0 (below threshold)
+        assert!(binary.data.iter().all(|&x| x == 0));
+    }
+
+    #[test]
+    fn test_rotation_detection_zero() {
+        let image = GrayImage::new(100, 100);
+        let angle = detect_rotation_angle(&image);
+        assert!((angle - 0.0).abs() < 1.0);
+    }
+
+    #[test]
+    fn test_rotation_detection_90_degrees() {
+        let image = GrayImage::from_fn(100, 100, |x, _| x as u8);
+        let angle = detect_rotation_angle(&image);
+        // In real implementation, should detect 0, 90, 180, or 270
+        assert!(angle >= -180.0 && angle <= 180.0);
+    }
+
+    #[test]
+    fn test_rotation_detection_180_degrees() {
+        let image = GrayImage::from_fn(100, 100, |x, y| ((x + y) % 256) as u8);
+        let angle = detect_rotation_angle(&image);
+        assert!(angle >= -180.0 && angle <= 180.0);
+    }
+
+    #[test]
+    fn test_rotation_detection_270_degrees() {
+        let image = GrayImage::new(100, 100);
+        let angle = detect_rotation_angle(&image);
+        assert!(angle >= -180.0 && angle <= 180.0);
+    }
+
+    #[test]
+    fn test_deskew_angle_detection() {
+        let image = GrayImage::new(100, 100);
+        let angle = deskew_angle(&image);
+
+        // Skew angle should typically be small (< 45 degrees)
+        assert!(angle.abs() < 45.0);
+    }
+
+    #[test]
+    fn test_deskew_angle_horizontal_lines() {
+        let image = GrayImage::from_fn(100, 100, |_, y| {
+            if y % 10 == 0 {
+                255
+            } else {
+                0
+            }
+        });
+
+        let angle = deskew_angle(&image);
+        // Should detect minimal skew for horizontal lines
+        assert!(angle.abs() < 5.0);
+    }
+
+    #[test]
+    fn test_clahe_enhancement() {
+        let image = GrayImage::from_fn(100, 100, |x, y| ((x + y) % 128) as u8);
+        let enhanced = apply_clahe(&image, 2.0);
+
+        assert_eq!(enhanced.width, image.width);
+        assert_eq!(enhanced.height, image.height);
+    }
+
+    #[test]
+    fn test_clahe_increases_contrast() {
+        let low_contrast = GrayImage::from_fn(50, 50, |x, _| (100 + x % 20) as u8);
+        let enhanced = apply_clahe(&low_contrast, 2.0);
+
+        // Calculate simple contrast measure
+        let original_range = calculate_range(&low_contrast);
+        let enhanced_range = calculate_range(&enhanced);
+
+        // Enhanced image should have equal or greater range
+        assert!(enhanced_range >= original_range);
+    }
+
+    #[test]
+    fn test_clahe_preserves_dimensions() {
+        let image = GrayImage::new(256, 256);
+        let enhanced = apply_clahe(&image, 2.0);
+
+        assert_eq!(enhanced.width, 256);
+        assert_eq!(enhanced.height, 256);
+    }
+
+    #[test]
+    fn test_clahe_different_clip_limits() {
+        let image = GrayImage::from_fn(50, 50, |x, y| ((x + y) % 256) as u8);
+
+        let clip_limits = vec![1.0, 2.0, 3.0, 4.0];
+        for limit in clip_limits {
+            let enhanced = apply_clahe(&image, limit);
+            assert_eq!(enhanced.width, image.width);
+            assert_eq!(enhanced.height, image.height);
+        }
+    }
+
+    #[test]
+    fn test_pipeline_chaining_blur_then_threshold() {
+        let image = GrayImage::from_fn(100, 100, |x, y| ((x + y) % 256) as u8);
+
+        // Chain operations
+        let blurred = gaussian_blur(&image, 1.0);
+        let threshold = otsu_threshold(&blurred);
+        let binary = apply_threshold(&blurred, threshold);
+
+        // Verify final result is binary
+        assert!(binary.data.iter().all(|&x| x == 0 || x == 255));
+    }
+
+    #[test]
+    fn test_pipeline_chaining_enhance_then_threshold() {
+        let image = GrayImage::from_fn(100, 100, |x, y| ((x + y) % 128) as u8);
+
+        // Chain CLAHE then threshold
+        let enhanced = apply_clahe(&image, 2.0);
+        let threshold = otsu_threshold(&enhanced);
+        let binary = apply_threshold(&enhanced, threshold);
+
+        assert!(binary.data.iter().all(|&x| x == 0 || x == 255));
+    }
+
+    #[test]
+    fn test_pipeline_full_preprocessing() {
+        let image = GrayImage::from_fn(100, 100, |x, y| ((x + y) % 256) as u8);
+
+        // Full pipeline: blur -> enhance -> threshold
+        let blurred = gaussian_blur(&image, 1.0);
+        let enhanced = apply_clahe(&blurred, 2.0);
+        let threshold = otsu_threshold(&enhanced);
+        let binary = apply_threshold(&enhanced, threshold);
+
+        assert_eq!(binary.width, image.width);
+        assert_eq!(binary.height, image.height);
+        assert!(binary.data.iter().all(|&x| x == 0 || x == 255));
+    }
+
+    #[test]
+    fn test_pipeline_preserves_dimensions_throughout() {
+        let image = GrayImage::new(200, 150);
+
+        let blurred = gaussian_blur(&image, 1.5);
+        assert_eq!((blurred.width, blurred.height), (200, 150));
+
+        let enhanced = apply_clahe(&blurred, 2.0);
+        assert_eq!((enhanced.width, enhanced.height), (200, 150));
+
+        let binary = apply_threshold(&enhanced, 128);
+        assert_eq!((binary.width, binary.height), (200, 150));
+    }
+
+    // Helper functions
+    fn calculate_range(image: &GrayImage) -> u8 {
+        let min = *image.data.iter().min().unwrap_or(&0);
+        let max = *image.data.iter().max().unwrap_or(&255);
+        max - min
+    }
+
+    #[test]
+    fn test_edge_case_empty_like_image() {
+        let tiny = GrayImage::new(1, 1);
+        assert_eq!(tiny.width, 1);
+        assert_eq!(tiny.height, 1);
+    }
+
+    #[test]
+    fn test_edge_case_large_image_dimensions() {
+        let large = GrayImage::new(4096, 4096);
+        assert_eq!(large.width, 4096);
+        assert_eq!(large.height, 4096);
+    }
+}