feat: Add sal-text crate

- Add a new crate `sal-text` for text manipulation utilities.
- Integrate `sal-text` into the main `sal` crate.
- Remove the previous `text` module from `sal`.  This improves
  organization and allows for independent development of the
  `sal-text` library.

text/tests/rhai/run_all_tests.rhai

@@ -0,0 +1,255 @@
+// Text Rhai Test Runner
+//
+// This script runs all Text-related Rhai tests and reports results.
+
+print("=== Text Rhai Test Suite ===");
+print("Running comprehensive tests for Text Rhai integration...\n");
+
+let total_tests = 0;
+let passed_tests = 0;
+let failed_tests = 0;
+
+// Test 1: Text Indentation Functions
+print("Test 1: Text Indentation Functions");
+total_tests += 1;
+try {
+    let indented = "    line 1\n    line 2\n        line 3";
+    let dedented = dedent(indented);
+    
+    let text = "line 1\nline 2";
+    let prefixed = prefix(text, "> ");
+    
+    if dedented == "line 1\nline 2\n    line 3" && prefixed == "> line 1\n> line 2" {
+        passed_tests += 1;
+        print("✓ PASSED: Text indentation functions work correctly");
+    } else {
+        failed_tests += 1;
+        print("✗ FAILED: Text indentation functions returned unexpected results");
+    }
+} catch(err) {
+    failed_tests += 1;
+    print(`✗ ERROR: Text indentation test failed - ${err}`);
+}
+
+// Test 2: String Normalization Functions
+print("\nTest 2: String Normalization Functions");
+total_tests += 1;
+try {
+    let unsafe_name = "User's File [Draft].txt";
+    let safe_name = name_fix(unsafe_name);
+    
+    let unsafe_path = "/path/to/User's File.txt";
+    let safe_path = path_fix(unsafe_path);
+    
+    if safe_name == "user_s_file_draft_.txt" && safe_path == "/path/to/user_s_file.txt" {
+        passed_tests += 1;
+        print("✓ PASSED: String normalization functions work correctly");
+    } else {
+        failed_tests += 1;
+        print(`✗ FAILED: String normalization - expected 'user_s_file_draft_.txt' and '/path/to/user_s_file.txt', got '${safe_name}' and '${safe_path}'`);
+    }
+} catch(err) {
+    failed_tests += 1;
+    print(`✗ ERROR: String normalization test failed - ${err}`);
+}
+
+// Test 3: TextReplacer Builder Pattern
+print("\nTest 3: TextReplacer Builder Pattern");
+total_tests += 1;
+try {
+    let builder = text_replacer_new();
+    builder = pattern(builder, "hello");
+    builder = replacement(builder, "hi");
+    builder = regex(builder, false);
+    
+    let replacer = build(builder);
+    let result = replace(replacer, "hello world, hello universe");
+    
+    if result == "hi world, hi universe" {
+        passed_tests += 1;
+        print("✓ PASSED: TextReplacer builder pattern works correctly");
+    } else {
+        failed_tests += 1;
+        print(`✗ FAILED: TextReplacer - expected 'hi world, hi universe', got '${result}'`);
+    }
+} catch(err) {
+    failed_tests += 1;
+    print(`✗ ERROR: TextReplacer builder test failed - ${err}`);
+}
+
+// Test 4: TextReplacer with Regex
+print("\nTest 4: TextReplacer with Regex");
+total_tests += 1;
+try {
+    let builder = text_replacer_new();
+    builder = pattern(builder, "\\d+");
+    builder = replacement(builder, "NUMBER");
+    builder = regex(builder, true);
+    
+    let replacer = build(builder);
+    let result = replace(replacer, "There are 123 items and 456 more");
+    
+    if result == "There are NUMBER items and NUMBER more" {
+        passed_tests += 1;
+        print("✓ PASSED: TextReplacer regex functionality works correctly");
+    } else {
+        failed_tests += 1;
+        print(`✗ FAILED: TextReplacer regex - expected 'There are NUMBER items and NUMBER more', got '${result}'`);
+    }
+} catch(err) {
+    failed_tests += 1;
+    print(`✗ ERROR: TextReplacer regex test failed - ${err}`);
+}
+
+// Test 5: TextReplacer Chained Operations
+print("\nTest 5: TextReplacer Chained Operations");
+total_tests += 1;
+try {
+    let builder = text_replacer_new();
+    builder = pattern(builder, "world");
+    builder = replacement(builder, "universe");
+    builder = regex(builder, false);
+    builder = and(builder);
+    builder = pattern(builder, "\\d+");
+    builder = replacement(builder, "NUMBER");
+    builder = regex(builder, true);
+    
+    let replacer = build(builder);
+    let result = replace(replacer, "Hello world, there are 123 items");
+    
+    if result == "Hello universe, there are NUMBER items" {
+        passed_tests += 1;
+        print("✓ PASSED: TextReplacer chained operations work correctly");
+    } else {
+        failed_tests += 1;
+        print(`✗ FAILED: TextReplacer chained - expected 'Hello universe, there are NUMBER items', got '${result}'`);
+    }
+} catch(err) {
+    failed_tests += 1;
+    print(`✗ ERROR: TextReplacer chained operations test failed - ${err}`);
+}
+
+// Test 6: Error Handling - Invalid Regex
+print("\nTest 6: Error Handling - Invalid Regex");
+total_tests += 1;
+try {
+    let builder = text_replacer_new();
+    builder = pattern(builder, "[invalid regex");
+    builder = replacement(builder, "test");
+    builder = regex(builder, true);
+    let replacer = build(builder);
+    
+    failed_tests += 1;
+    print("✗ FAILED: Should have failed with invalid regex");
+} catch(err) {
+    passed_tests += 1;
+    print("✓ PASSED: Invalid regex properly rejected");
+}
+
+// Test 7: Unicode Handling
+print("\nTest 7: Unicode Handling");
+total_tests += 1;
+try {
+    let unicode_text = "    Hello 世界\n    Goodbye 世界";
+    let dedented = dedent(unicode_text);
+    
+    let unicode_name = "Café";
+    let fixed_name = name_fix(unicode_name);
+    
+    let unicode_prefix = prefix("Hello 世界", "🔹 ");
+    
+    if dedented == "Hello 世界\nGoodbye 世界" && 
+       fixed_name == "caf" && 
+       unicode_prefix == "🔹 Hello 世界" {
+        passed_tests += 1;
+        print("✓ PASSED: Unicode handling works correctly");
+    } else {
+        failed_tests += 1;
+        print("✗ FAILED: Unicode handling returned unexpected results");
+    }
+} catch(err) {
+    failed_tests += 1;
+    print(`✗ ERROR: Unicode handling test failed - ${err}`);
+}
+
+// Test 8: Edge Cases
+print("\nTest 8: Edge Cases");
+total_tests += 1;
+try {
+    let empty_dedent = dedent("");
+    let empty_prefix = prefix("test", "");
+    let empty_name_fix = name_fix("");
+    
+    if empty_dedent == "" && empty_prefix == "test" && empty_name_fix == "" {
+        passed_tests += 1;
+        print("✓ PASSED: Edge cases handled correctly");
+    } else {
+        failed_tests += 1;
+        print("✗ FAILED: Edge cases returned unexpected results");
+    }
+} catch(err) {
+    failed_tests += 1;
+    print(`✗ ERROR: Edge cases test failed - ${err}`);
+}
+
+// Test 9: Complex Workflow
+print("\nTest 9: Complex Text Processing Workflow");
+total_tests += 1;
+try {
+    // Normalize filename
+    let unsafe_filename = "User's Script [Draft].py";
+    let safe_filename = name_fix(unsafe_filename);
+    
+    // Process code
+    let indented_code = "    def hello():\n        print('Hello World')\n        return True";
+    let dedented_code = dedent(indented_code);
+    let commented_code = prefix(dedented_code, "# ");
+    
+    // Replace text
+    let builder = text_replacer_new();
+    builder = pattern(builder, "Hello World");
+    builder = replacement(builder, "SAL Text");
+    builder = regex(builder, false);
+    
+    let replacer = build(builder);
+    let final_code = replace(replacer, commented_code);
+    
+    if safe_filename == "user_s_script_draft_.py" &&
+       final_code.contains("# def hello():") && 
+       final_code.contains("SAL Text") {
+        passed_tests += 1;
+        print("✓ PASSED: Complex workflow completed successfully");
+    } else {
+        failed_tests += 1;
+        print("✗ FAILED: Complex workflow returned unexpected results");
+    }
+} catch(err) {
+    failed_tests += 1;
+    print(`✗ ERROR: Complex workflow test failed - ${err}`);
+}
+
+// Test 10: Template Builder Error Handling
+print("\nTest 10: Template Builder Error Handling");
+total_tests += 1;
+try {
+    let builder = template_builder_open("/nonexistent/file.txt");
+    failed_tests += 1;
+    print("✗ FAILED: Should have failed with nonexistent file");
+} catch(err) {
+    passed_tests += 1;
+    print("✓ PASSED: Template builder properly handles nonexistent files");
+}
+
+// Print final results
+print("\n=== Test Results ===");
+print(`Total Tests: ${total_tests}`);
+print(`Passed: ${passed_tests}`);
+print(`Failed: ${failed_tests}`);
+
+if failed_tests == 0 {
+    print("\n✓ All tests passed!");
+} else {
+    print(`\n✗ ${failed_tests} test(s) failed.`);
+}
+
+print("\n=== Text Rhai Test Suite Completed ===");

text/tests/rhai_integration_tests.rs

@@ -0,0 +1,351 @@
+//! Rhai integration tests for Text module
+//!
+//! These tests validate the Rhai wrapper functions and ensure proper
+//! integration between Rust and Rhai for text processing operations.
+
+use rhai::{Engine, EvalAltResult};
+use sal_text::rhai::*;
+
+#[cfg(test)]
+mod rhai_integration_tests {
+    use super::*;
+
+    fn create_test_engine() -> Engine {
+        let mut engine = Engine::new();
+        register_text_module(&mut engine).expect("Failed to register text module");
+        engine
+    }
+
+    #[test]
+    fn test_rhai_module_registration() {
+        let engine = create_test_engine();
+
+        // Test that the functions are registered by checking if they exist
+        let script = r#"
+            // Test that all text functions are available
+            let functions_exist = true;
+            functions_exist
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_dedent_function_exists() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let indented = "    line 1\n    line 2\n        line 3";
+            let result = dedent(indented);
+            return result == "line 1\nline 2\n    line 3";
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_prefix_function_exists() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let text = "line 1\nline 2";
+            let result = prefix(text, "> ");
+            return result == "> line 1\n> line 2";
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_name_fix_function_exists() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let unsafe_name = "User's File [Draft].txt";
+            let result = name_fix(unsafe_name);
+            return result == "users_file_draft_.txt";
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_path_fix_function_exists() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let unsafe_path = "/path/to/User's File.txt";
+            let result = path_fix(unsafe_path);
+            return result == "/path/to/users_file.txt";
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_text_replacer_builder_creation() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let builder = text_replacer_builder();
+            return type_of(builder) == "sal_text::replace::TextReplacerBuilder";
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_text_replacer_workflow() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let builder = text_replacer_builder();
+            builder = pattern(builder, "hello");
+            builder = replacement(builder, "hi");
+            builder = regex(builder, false);
+            
+            let replacer = build(builder);
+            let result = replace(replacer, "hello world, hello universe");
+            
+            return result == "hi world, hi universe";
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_text_replacer_regex_workflow() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let builder = text_replacer_builder();
+            builder = pattern(builder, r"\d+");
+            builder = replacement(builder, "NUMBER");
+            builder = regex(builder, true);
+            
+            let replacer = build(builder);
+            let result = replace(replacer, "There are 123 items");
+            
+            return result == "There are NUMBER items";
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_text_replacer_chained_operations() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let builder = text_replacer_builder();
+            builder = pattern(builder, "world");
+            builder = replacement(builder, "universe");
+            builder = regex(builder, false);
+            builder = and(builder);
+            builder = pattern(builder, r"\d+");
+            builder = replacement(builder, "NUMBER");
+            builder = regex(builder, true);
+            
+            let replacer = build(builder);
+            let result = replace(replacer, "Hello world, there are 123 items");
+            
+            return result == "Hello universe, there are NUMBER items";
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_template_builder_creation() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            // We can't test file operations easily in unit tests,
+            // but we can test that the function exists and returns the right type
+            try {
+                let builder = template_builder_open("/nonexistent/file.txt");
+                return false; // Should have failed
+            } catch(err) {
+                return err.to_string().contains("error"); // Expected to fail
+            }
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_error_handling_invalid_regex() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            try {
+                let builder = text_replacer_builder();
+                builder = pattern(builder, "[invalid regex");
+                builder = replacement(builder, "test");
+                builder = regex(builder, true);
+                let replacer = build(builder);
+                return false; // Should have failed
+            } catch(err) {
+                return true; // Expected to fail
+            }
+        "#;
+
+        let result: Result<bool, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        assert_eq!(result.unwrap(), true);
+    }
+
+    #[test]
+    fn test_parameter_validation() {
+        let engine = create_test_engine();
+
+        // Test that functions handle parameter validation correctly
+        let script = r#"
+            let test_results = [];
+            
+            // Test empty string handling
+            try {
+                let result = dedent("");
+                test_results.push(result == "");
+            } catch(err) {
+                test_results.push(false);
+            }
+            
+            // Test empty prefix
+            try {
+                let result = prefix("test", "");
+                test_results.push(result == "test");
+            } catch(err) {
+                test_results.push(false);
+            }
+            
+            // Test empty name_fix
+            try {
+                let result = name_fix("");
+                test_results.push(result == "");
+            } catch(err) {
+                test_results.push(false);
+            }
+            
+            return test_results;
+        "#;
+
+        let result: Result<rhai::Array, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        let results = result.unwrap();
+
+        // All parameter validation tests should pass
+        for (i, result) in results.iter().enumerate() {
+            assert_eq!(
+                result.as_bool().unwrap_or(false),
+                true,
+                "Parameter validation test {} failed",
+                i
+            );
+        }
+    }
+
+    #[test]
+    fn test_unicode_handling() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            let unicode_tests = [];
+            
+            // Test dedent with unicode
+            try {
+                let text = "    Hello 世界\n    Goodbye 世界";
+                let result = dedent(text);
+                unicode_tests.push(result == "Hello 世界\nGoodbye 世界");
+            } catch(err) {
+                unicode_tests.push(false);
+            }
+            
+            // Test name_fix with unicode (should remove non-ASCII)
+            try {
+                let result = name_fix("Café");
+                unicode_tests.push(result == "caf");
+            } catch(err) {
+                unicode_tests.push(false);
+            }
+            
+            // Test prefix with unicode
+            try {
+                let result = prefix("Hello 世界", "🔹 ");
+                unicode_tests.push(result == "🔹 Hello 世界");
+            } catch(err) {
+                unicode_tests.push(false);
+            }
+            
+            return unicode_tests;
+        "#;
+
+        let result: Result<rhai::Array, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        let results = result.unwrap();
+
+        // All unicode tests should pass
+        for (i, result) in results.iter().enumerate() {
+            assert_eq!(
+                result.as_bool().unwrap_or(false),
+                true,
+                "Unicode test {} failed",
+                i
+            );
+        }
+    }
+
+    #[test]
+    fn test_complex_text_processing_workflow() {
+        let engine = create_test_engine();
+
+        let script = r#"
+            // Simple workflow test
+            let unsafe_filename = "User's Script [Draft].py";
+            let safe_filename = name_fix(unsafe_filename);
+
+            let indented_code = "    def hello():\n        return True";
+            let dedented_code = dedent(indented_code);
+
+            let results = [];
+            results.push(safe_filename == "users_script_draft_.py");
+            results.push(dedented_code.contains("def hello():"));
+
+            return results;
+        "#;
+
+        let result: Result<rhai::Array, Box<EvalAltResult>> = engine.eval(script);
+        assert!(result.is_ok());
+        let results = result.unwrap();
+
+        // All workflow tests should pass
+        for (i, result) in results.iter().enumerate() {
+            assert_eq!(
+                result.as_bool().unwrap_or(false),
+                true,
+                "Workflow test {} failed",
+                i
+            );
+        }
+    }
+}

text/tests/string_normalization_tests.rs

@@ -0,0 +1,174 @@
+//! Unit tests for string normalization functionality
+//!
+//! These tests validate the name_fix and path_fix functions including:
+//! - Filename sanitization for safe filesystem usage
+//! - Path normalization preserving directory structure
+//! - Special character handling and replacement
+//! - Unicode character removal and ASCII conversion
+
+use sal_text::{name_fix, path_fix};
+
+#[test]
+fn test_name_fix_basic() {
+    assert_eq!(name_fix("Hello World"), "hello_world");
+    assert_eq!(name_fix("File-Name.txt"), "file_name.txt");
+}
+
+#[test]
+fn test_name_fix_special_characters() {
+    assert_eq!(name_fix("Test!@#$%^&*()"), "test_");
+    assert_eq!(name_fix("Space, Tab\t, Comma,"), "space_tab_comma_");
+    assert_eq!(name_fix("Quotes\"'"), "quotes_");
+    assert_eq!(name_fix("Brackets[]<>"), "brackets_");
+    assert_eq!(name_fix("Operators=+-"), "operators_");
+}
+
+#[test]
+fn test_name_fix_unicode_removal() {
+    assert_eq!(name_fix("Café"), "caf");
+    assert_eq!(name_fix("Résumé"), "rsum");
+    assert_eq!(name_fix("Über"), "ber");
+    assert_eq!(name_fix("Naïve"), "nave");
+    assert_eq!(name_fix("Piñata"), "piata");
+}
+
+#[test]
+fn test_name_fix_case_conversion() {
+    assert_eq!(name_fix("UPPERCASE"), "uppercase");
+    assert_eq!(name_fix("MixedCase"), "mixedcase");
+    assert_eq!(name_fix("camelCase"), "camelcase");
+    assert_eq!(name_fix("PascalCase"), "pascalcase");
+}
+
+#[test]
+fn test_name_fix_consecutive_underscores() {
+    assert_eq!(name_fix("Multiple   Spaces"), "multiple_spaces");
+    assert_eq!(name_fix("Special!!!Characters"), "special_characters");
+    assert_eq!(name_fix("Mixed-_-Separators"), "mixed_separators");
+}
+
+#[test]
+fn test_name_fix_file_extensions() {
+    assert_eq!(name_fix("Document.PDF"), "document.pdf");
+    assert_eq!(name_fix("Image.JPEG"), "image.jpeg");
+    assert_eq!(name_fix("Archive.tar.gz"), "archive.tar.gz");
+    assert_eq!(name_fix("Config.json"), "config.json");
+}
+
+#[test]
+fn test_name_fix_empty_and_edge_cases() {
+    assert_eq!(name_fix(""), "");
+    assert_eq!(name_fix("   "), "_");
+    assert_eq!(name_fix("!!!"), "_");
+    assert_eq!(name_fix("___"), "_");
+}
+
+#[test]
+fn test_name_fix_real_world_examples() {
+    assert_eq!(name_fix("User's Report [Draft 1].md"), "users_report_draft_1_.md");
+    assert_eq!(name_fix("Meeting Notes (2023-12-01).txt"), "meeting_notes_2023_12_01_.txt");
+    assert_eq!(name_fix("Photo #123 - Vacation!.jpg"), "photo_123_vacation_.jpg");
+    assert_eq!(name_fix("Project Plan v2.0 FINAL.docx"), "project_plan_v2.0_final.docx");
+}
+
+#[test]
+fn test_path_fix_directory_paths() {
+    assert_eq!(path_fix("/path/to/directory/"), "/path/to/directory/");
+    assert_eq!(path_fix("./relative/path/"), "./relative/path/");
+    assert_eq!(path_fix("../parent/path/"), "../parent/path/");
+}
+
+#[test]
+fn test_path_fix_single_filename() {
+    assert_eq!(path_fix("filename.txt"), "filename.txt");
+    assert_eq!(path_fix("UPPER-file.md"), "upper_file.md");
+    assert_eq!(path_fix("Special!File.pdf"), "special_file.pdf");
+}
+
+#[test]
+fn test_path_fix_absolute_paths() {
+    assert_eq!(path_fix("/path/to/File Name.txt"), "/path/to/file_name.txt");
+    assert_eq!(path_fix("/absolute/path/to/DOCUMENT-123.pdf"), "/absolute/path/to/document_123.pdf");
+    assert_eq!(path_fix("/home/user/Résumé.doc"), "/home/user/rsum.doc");
+}
+
+#[test]
+fn test_path_fix_relative_paths() {
+    assert_eq!(path_fix("./relative/path/to/Document.PDF"), "./relative/path/to/document.pdf");
+    assert_eq!(path_fix("../parent/Special File.txt"), "../parent/special_file.txt");
+    assert_eq!(path_fix("subfolder/User's File.md"), "subfolder/users_file.md");
+}
+
+#[test]
+fn test_path_fix_special_characters_in_filename() {
+    assert_eq!(path_fix("/path/with/[special]<chars>.txt"), "/path/with/_special_chars_.txt");
+    assert_eq!(path_fix("./folder/File!@#.pdf"), "./folder/file_.pdf");
+    assert_eq!(path_fix("/data/Report (Final).docx"), "/data/report_final_.docx");
+}
+
+#[test]
+fn test_path_fix_preserves_path_structure() {
+    assert_eq!(path_fix("/very/long/path/to/some/Deep File.txt"), "/very/long/path/to/some/deep_file.txt");
+    assert_eq!(path_fix("./a/b/c/d/e/Final Document.pdf"), "./a/b/c/d/e/final_document.pdf");
+}
+
+#[test]
+fn test_path_fix_windows_style_paths() {
+    // Note: These tests assume Unix-style path handling
+    // In a real implementation, you might want to handle Windows paths differently
+    assert_eq!(path_fix("C:\\Users\\Name\\Document.txt"), "c_users_name_document.txt");
+}
+
+#[test]
+fn test_path_fix_edge_cases() {
+    assert_eq!(path_fix(""), "");
+    assert_eq!(path_fix("/"), "/");
+    assert_eq!(path_fix("./"), "./");
+    assert_eq!(path_fix("../"), "../");
+}
+
+#[test]
+fn test_path_fix_unicode_in_filename() {
+    assert_eq!(path_fix("/path/to/Café.txt"), "/path/to/caf.txt");
+    assert_eq!(path_fix("./folder/Naïve Document.pdf"), "./folder/nave_document.pdf");
+    assert_eq!(path_fix("/home/user/Piñata Party.jpg"), "/home/user/piata_party.jpg");
+}
+
+#[test]
+fn test_path_fix_complex_real_world_examples() {
+    assert_eq!(
+        path_fix("/Users/john/Documents/Project Files/Final Report (v2.1) [APPROVED].docx"),
+        "/Users/john/Documents/Project Files/final_report_v2.1_approved_.docx"
+    );
+    
+    assert_eq!(
+        path_fix("./assets/images/Photo #123 - Vacation! (2023).jpg"),
+        "./assets/images/photo_123_vacation_2023_.jpg"
+    );
+    
+    assert_eq!(
+        path_fix("/var/log/Application Logs/Error Log [2023-12-01].txt"),
+        "/var/log/Application Logs/error_log_2023_12_01_.txt"
+    );
+}
+
+#[test]
+fn test_name_fix_and_path_fix_consistency() {
+    let filename = "User's Report [Draft].txt";
+    let path = "/path/to/User's Report [Draft].txt";
+    
+    let fixed_name = name_fix(filename);
+    let fixed_path = path_fix(path);
+    
+    // The filename part should be the same in both cases
+    assert!(fixed_path.ends_with(&fixed_name));
+    assert_eq!(fixed_name, "users_report_draft_.txt");
+    assert_eq!(fixed_path, "/path/to/users_report_draft_.txt");
+}
+
+#[test]
+fn test_normalization_preserves_dots_in_extensions() {
+    assert_eq!(name_fix("file.tar.gz"), "file.tar.gz");
+    assert_eq!(name_fix("backup.2023.12.01.sql"), "backup.2023.12.01.sql");
+    assert_eq!(path_fix("/path/to/archive.tar.bz2"), "/path/to/archive.tar.bz2");
+}

text/tests/template_tests.rs

@@ -0,0 +1,297 @@
+//! Unit tests for template functionality
+//!
+//! These tests validate the TemplateBuilder including:
+//! - Template loading from files
+//! - Variable substitution (string, int, float, bool, array)
+//! - Template rendering to string and file
+//! - Error handling for missing variables and invalid templates
+//! - Complex template scenarios with loops and conditionals
+
+use sal_text::TemplateBuilder;
+use std::collections::HashMap;
+use std::fs;
+use tempfile::NamedTempFile;
+
+#[test]
+fn test_template_builder_basic_string_variable() {
+    // Create a temporary template file
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "Hello {{name}}!";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("name", "World")
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result, "Hello World!");
+}
+
+#[test]
+fn test_template_builder_multiple_variables() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "{{greeting}} {{name}}, you have {{count}} messages.";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("greeting", "Hello")
+        .add_var("name", "Alice")
+        .add_var("count", 5)
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result, "Hello Alice, you have 5 messages.");
+}
+
+#[test]
+fn test_template_builder_different_types() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "String: {{text}}, Int: {{number}}, Float: {{decimal}}, Bool: {{flag}}";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("text", "hello")
+        .add_var("number", 42)
+        .add_var("decimal", 3.14)
+        .add_var("flag", true)
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result, "String: hello, Int: 42, Float: 3.14, Bool: true");
+}
+
+#[test]
+fn test_template_builder_array_variable() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "Items: {% for item in items %}{{item}}{% if not loop.last %}, {% endif %}{% endfor %}";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let items = vec!["apple", "banana", "cherry"];
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("items", items)
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result, "Items: apple, banana, cherry");
+}
+
+#[test]
+fn test_template_builder_add_vars_hashmap() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "{{title}}: {{description}}";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let mut vars = HashMap::new();
+    vars.insert("title".to_string(), "Report".to_string());
+    vars.insert("description".to_string(), "Monthly summary".to_string());
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_vars(vars)
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result, "Report: Monthly summary");
+}
+
+#[test]
+fn test_template_builder_render_to_file() {
+    // Create template file
+    let mut template_file = NamedTempFile::new().expect("Failed to create template file");
+    let template_content = "Hello {{name}}, today is {{day}}.";
+    fs::write(template_file.path(), template_content).expect("Failed to write template");
+
+    // Create output file
+    let output_file = NamedTempFile::new().expect("Failed to create output file");
+
+    TemplateBuilder::open(template_file.path())
+        .expect("Failed to open template")
+        .add_var("name", "Bob")
+        .add_var("day", "Monday")
+        .render_to_file(output_file.path())
+        .expect("Failed to render to file");
+
+    let result = fs::read_to_string(output_file.path()).expect("Failed to read output file");
+    assert_eq!(result, "Hello Bob, today is Monday.");
+}
+
+#[test]
+fn test_template_builder_conditional() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "{% if show_message %}Message: {{message}}{% else %}No message{% endif %}";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    // Test with condition true
+    let result_true = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("show_message", true)
+        .add_var("message", "Hello World")
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result_true, "Message: Hello World");
+
+    // Test with condition false
+    let result_false = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("show_message", false)
+        .add_var("message", "Hello World")
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result_false, "No message");
+}
+
+#[test]
+fn test_template_builder_loop_with_index() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "{% for item in items %}{{loop.index}}: {{item}}\n{% endfor %}";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let items = vec!["first", "second", "third"];
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("items", items)
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result, "1: first\n2: second\n3: third\n");
+}
+
+#[test]
+fn test_template_builder_nested_variables() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "User: {{user.name}} ({{user.email}})";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let mut user = HashMap::new();
+    user.insert("name".to_string(), "John Doe".to_string());
+    user.insert("email".to_string(), "john@example.com".to_string());
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("user", user)
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result, "User: John Doe (john@example.com)");
+}
+
+#[test]
+fn test_template_builder_missing_variable_error() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "Hello {{missing_var}}!";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .render();
+
+    assert!(result.is_err());
+}
+
+#[test]
+fn test_template_builder_invalid_template_syntax() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "Hello {{unclosed_var!";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .render();
+
+    assert!(result.is_err());
+}
+
+#[test]
+fn test_template_builder_nonexistent_file() {
+    let result = TemplateBuilder::open("/nonexistent/template.txt");
+    assert!(result.is_err());
+}
+
+#[test]
+fn test_template_builder_empty_template() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    fs::write(temp_file.path(), "").expect("Failed to write empty template");
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .render()
+        .expect("Failed to render empty template");
+
+    assert_eq!(result, "");
+}
+
+#[test]
+fn test_template_builder_template_with_no_variables() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = "This is a static template with no variables.";
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .render()
+        .expect("Failed to render template");
+
+    assert_eq!(result, template_content);
+}
+
+#[test]
+fn test_template_builder_complex_report() {
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content = r#"
+# {{report_title}}
+
+Generated on: {{date}}
+
+## Summary
+Total items: {{total_items}}
+Status: {{status}}
+
+## Items
+{% for item in items %}
+- {{item.name}}: {{item.value}}{% if item.important %} (IMPORTANT){% endif %}
+{% endfor %}
+
+## Footer
+{% if show_footer %}
+Report generated by {{generator}}
+{% endif %}
+"#;
+    fs::write(temp_file.path(), template_content).expect("Failed to write template");
+
+    let mut item1 = HashMap::new();
+    item1.insert("name".to_string(), "Item 1".to_string());
+    item1.insert("value".to_string(), "100".to_string());
+    item1.insert("important".to_string(), true.to_string());
+
+    let mut item2 = HashMap::new();
+    item2.insert("name".to_string(), "Item 2".to_string());
+    item2.insert("value".to_string(), "200".to_string());
+    item2.insert("important".to_string(), false.to_string());
+
+    let items = vec![item1, item2];
+
+    let result = TemplateBuilder::open(temp_file.path())
+        .expect("Failed to open template")
+        .add_var("report_title", "Monthly Report")
+        .add_var("date", "2023-12-01")
+        .add_var("total_items", 2)
+        .add_var("status", "Complete")
+        .add_var("items", items)
+        .add_var("show_footer", true)
+        .add_var("generator", "SAL Text")
+        .render()
+        .expect("Failed to render template");
+
+    assert!(result.contains("# Monthly Report"));
+    assert!(result.contains("Generated on: 2023-12-01"));
+    assert!(result.contains("Total items: 2"));
+    assert!(result.contains("- Item 1: 100"));
+    assert!(result.contains("- Item 2: 200"));
+    assert!(result.contains("Report generated by SAL Text"));
+}

text/tests/text_indentation_tests.rs

@@ -0,0 +1,159 @@
+//! Unit tests for text indentation functionality
+//!
+//! These tests validate the dedent and prefix functions including:
+//! - Common whitespace removal (dedent)
+//! - Line prefix addition (prefix)
+//! - Edge cases and special characters
+//! - Tab handling and mixed indentation
+
+use sal_text::{dedent, prefix};
+
+#[test]
+fn test_dedent_basic() {
+    let indented = "    line 1\n    line 2\n        line 3";
+    let expected = "line 1\nline 2\n    line 3";
+    assert_eq!(dedent(indented), expected);
+}
+
+#[test]
+fn test_dedent_empty_lines() {
+    let indented = "    line 1\n\n    line 2\n        line 3";
+    let expected = "line 1\n\nline 2\n    line 3";
+    assert_eq!(dedent(indented), expected);
+}
+
+#[test]
+fn test_dedent_tabs_as_spaces() {
+    let indented = "\t\tline 1\n\t\tline 2\n\t\t\tline 3";
+    let expected = "line 1\nline 2\n\tline 3";
+    assert_eq!(dedent(indented), expected);
+}
+
+#[test]
+fn test_dedent_mixed_tabs_and_spaces() {
+    let indented = "    \tline 1\n    \tline 2\n    \t    line 3";
+    let expected = "line 1\nline 2\n    line 3";
+    assert_eq!(dedent(indented), expected);
+}
+
+#[test]
+fn test_dedent_no_common_indentation() {
+    let text = "line 1\n  line 2\n    line 3";
+    let expected = "line 1\n  line 2\n    line 3";
+    assert_eq!(dedent(text), expected);
+}
+
+#[test]
+fn test_dedent_single_line() {
+    let indented = "    single line";
+    let expected = "single line";
+    assert_eq!(dedent(indented), expected);
+}
+
+#[test]
+fn test_dedent_empty_string() {
+    assert_eq!(dedent(""), "");
+}
+
+#[test]
+fn test_dedent_only_whitespace() {
+    let whitespace = "    \n        \n    ";
+    let expected = "\n\n";
+    assert_eq!(dedent(whitespace), expected);
+}
+
+#[test]
+fn test_prefix_basic() {
+    let text = "line 1\nline 2\nline 3";
+    let expected = "    line 1\n    line 2\n    line 3";
+    assert_eq!(prefix(text, "    "), expected);
+}
+
+#[test]
+fn test_prefix_with_symbols() {
+    let text = "line 1\nline 2\nline 3";
+    let expected = "> line 1\n> line 2\n> line 3";
+    assert_eq!(prefix(text, "> "), expected);
+}
+
+#[test]
+fn test_prefix_empty_lines() {
+    let text = "line 1\n\nline 3";
+    let expected = ">> line 1\n>> \n>> line 3";
+    assert_eq!(prefix(text, ">> "), expected);
+}
+
+#[test]
+fn test_prefix_single_line() {
+    let text = "single line";
+    let expected = "PREFIX: single line";
+    assert_eq!(prefix(text, "PREFIX: "), expected);
+}
+
+#[test]
+fn test_prefix_empty_string() {
+    assert_eq!(prefix("", "PREFIX: "), "");
+}
+
+#[test]
+fn test_prefix_empty_prefix() {
+    let text = "line 1\nline 2";
+    assert_eq!(prefix(text, ""), text);
+}
+
+#[test]
+fn test_dedent_and_prefix_combination() {
+    let indented = "    def function():\n        print('hello')\n        return True";
+    let dedented = dedent(indented);
+    let prefixed = prefix(&dedented, ">>> ");
+    
+    let expected = ">>> def function():\n>>>     print('hello')\n>>>     return True";
+    assert_eq!(prefixed, expected);
+}
+
+#[test]
+fn test_dedent_real_code_example() {
+    let code = r#"
+        if condition:
+            for item in items:
+                process(item)
+            return result
+        else:
+            return None"#;
+    
+    let dedented = dedent(code);
+    let expected = "\nif condition:\n    for item in items:\n        process(item)\n    return result\nelse:\n    return None";
+    assert_eq!(dedented, expected);
+}
+
+#[test]
+fn test_prefix_code_comment() {
+    let code = "function main() {\n    console.log('Hello');\n}";
+    let commented = prefix(code, "// ");
+    let expected = "// function main() {\n//     console.log('Hello');\n// }";
+    assert_eq!(commented, expected);
+}
+
+#[test]
+fn test_dedent_preserves_relative_indentation() {
+    let text = "        start\n            indented more\n        back to start level\n            indented again";
+    let dedented = dedent(text);
+    let expected = "start\n    indented more\nback to start level\n    indented again";
+    assert_eq!(dedented, expected);
+}
+
+#[test]
+fn test_prefix_with_unicode() {
+    let text = "Hello 世界\nGoodbye 世界";
+    let prefixed = prefix(text, "🔹 ");
+    let expected = "🔹 Hello 世界\n🔹 Goodbye 世界";
+    assert_eq!(prefixed, expected);
+}
+
+#[test]
+fn test_dedent_with_unicode() {
+    let text = "    Hello 世界\n    Goodbye 世界\n        More indented 世界";
+    let dedented = dedent(text);
+    let expected = "Hello 世界\nGoodbye 世界\n    More indented 世界";
+    assert_eq!(dedented, expected);
+}

text/tests/text_replacement_tests.rs

@@ -0,0 +1,301 @@
+//! Unit tests for text replacement functionality
+//!
+//! These tests validate the TextReplacer and TextReplacerBuilder including:
+//! - Literal string replacement
+//! - Regex pattern replacement
+//! - Multiple chained replacements
+//! - File operations (read, write, in-place)
+//! - Error handling and edge cases
+
+use sal_text::{TextReplacer, TextReplacerBuilder};
+use std::fs;
+use tempfile::NamedTempFile;
+
+#[test]
+fn test_text_replacer_literal_single() {
+    let replacer = TextReplacer::builder()
+        .pattern("hello")
+        .replacement("hi")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("hello world, hello universe");
+    assert_eq!(result, "hi world, hi universe");
+}
+
+#[test]
+fn test_text_replacer_regex_single() {
+    let replacer = TextReplacer::builder()
+        .pattern(r"\d+")
+        .replacement("NUMBER")
+        .regex(true)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("There are 123 items and 456 more");
+    assert_eq!(result, "There are NUMBER items and NUMBER more");
+}
+
+#[test]
+fn test_text_replacer_multiple_operations() {
+    let replacer = TextReplacer::builder()
+        .pattern(r"\d+")
+        .replacement("NUMBER")
+        .regex(true)
+        .and()
+        .pattern("world")
+        .replacement("universe")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("Hello world, there are 123 items");
+    assert_eq!(result, "Hello universe, there are NUMBER items");
+}
+
+#[test]
+fn test_text_replacer_chained_operations() {
+    let replacer = TextReplacer::builder()
+        .pattern("cat")
+        .replacement("dog")
+        .regex(false)
+        .and()
+        .pattern("dog")
+        .replacement("animal")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    // Operations are applied in sequence, so "cat" -> "dog" -> "animal"
+    let result = replacer.replace("The cat sat on the mat");
+    assert_eq!(result, "The animal sat on the mat");
+}
+
+#[test]
+fn test_text_replacer_regex_capture_groups() {
+    let replacer = TextReplacer::builder()
+        .pattern(r"(\d{4})-(\d{2})-(\d{2})")
+        .replacement("$3/$2/$1")
+        .regex(true)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("Date: 2023-12-01");
+    assert_eq!(result, "Date: 01/12/2023");
+}
+
+#[test]
+fn test_text_replacer_case_sensitive() {
+    let replacer = TextReplacer::builder()
+        .pattern("Hello")
+        .replacement("Hi")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("Hello world, hello universe");
+    assert_eq!(result, "Hi world, hello universe");
+}
+
+#[test]
+fn test_text_replacer_regex_case_insensitive() {
+    let replacer = TextReplacer::builder()
+        .pattern(r"(?i)hello")
+        .replacement("Hi")
+        .regex(true)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("Hello world, HELLO universe");
+    assert_eq!(result, "Hi world, Hi universe");
+}
+
+#[test]
+fn test_text_replacer_empty_input() {
+    let replacer = TextReplacer::builder()
+        .pattern("test")
+        .replacement("replacement")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("");
+    assert_eq!(result, "");
+}
+
+#[test]
+fn test_text_replacer_no_matches() {
+    let replacer = TextReplacer::builder()
+        .pattern("xyz")
+        .replacement("abc")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    let input = "Hello world";
+    let result = replacer.replace(input);
+    assert_eq!(result, input);
+}
+
+#[test]
+fn test_text_replacer_file_operations() {
+    // Create a temporary file with test content
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let test_content = "Hello world, there are 123 items";
+    fs::write(temp_file.path(), test_content).expect("Failed to write to temp file");
+
+    let replacer = TextReplacer::builder()
+        .pattern(r"\d+")
+        .replacement("NUMBER")
+        .regex(true)
+        .and()
+        .pattern("world")
+        .replacement("universe")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    // Test replace_file
+    let result = replacer.replace_file(temp_file.path()).expect("Failed to replace file content");
+    assert_eq!(result, "Hello universe, there are NUMBER items");
+
+    // Verify original file is unchanged
+    let original_content = fs::read_to_string(temp_file.path()).expect("Failed to read original file");
+    assert_eq!(original_content, test_content);
+}
+
+#[test]
+fn test_text_replacer_file_in_place() {
+    // Create a temporary file with test content
+    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let test_content = "Hello world, there are 123 items";
+    fs::write(temp_file.path(), test_content).expect("Failed to write to temp file");
+
+    let replacer = TextReplacer::builder()
+        .pattern("world")
+        .replacement("universe")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    // Test replace_file_in_place
+    replacer.replace_file_in_place(temp_file.path()).expect("Failed to replace file in place");
+
+    // Verify file content was changed
+    let new_content = fs::read_to_string(temp_file.path()).expect("Failed to read modified file");
+    assert_eq!(new_content, "Hello universe, there are 123 items");
+}
+
+#[test]
+fn test_text_replacer_file_to_file() {
+    // Create source file
+    let mut source_file = NamedTempFile::new().expect("Failed to create source file");
+    let test_content = "Hello world, there are 123 items";
+    fs::write(source_file.path(), test_content).expect("Failed to write to source file");
+
+    // Create destination file
+    let dest_file = NamedTempFile::new().expect("Failed to create dest file");
+
+    let replacer = TextReplacer::builder()
+        .pattern(r"\d+")
+        .replacement("NUMBER")
+        .regex(true)
+        .build()
+        .expect("Failed to build replacer");
+
+    // Test replace_file_to
+    replacer.replace_file_to(source_file.path(), dest_file.path())
+        .expect("Failed to replace file to destination");
+
+    // Verify source file is unchanged
+    let source_content = fs::read_to_string(source_file.path()).expect("Failed to read source file");
+    assert_eq!(source_content, test_content);
+
+    // Verify destination file has replaced content
+    let dest_content = fs::read_to_string(dest_file.path()).expect("Failed to read dest file");
+    assert_eq!(dest_content, "Hello world, there are NUMBER items");
+}
+
+#[test]
+fn test_text_replacer_invalid_regex() {
+    let result = TextReplacer::builder()
+        .pattern("[invalid regex")
+        .replacement("test")
+        .regex(true)
+        .build();
+
+    assert!(result.is_err());
+}
+
+#[test]
+fn test_text_replacer_builder_default_regex_false() {
+    let replacer = TextReplacer::builder()
+        .pattern(r"\d+")
+        .replacement("NUMBER")
+        .build()
+        .expect("Failed to build replacer");
+
+    // Should treat as literal since regex defaults to false
+    let result = replacer.replace(r"Match \d+ pattern");
+    assert_eq!(result, "Match NUMBER pattern");
+}
+
+#[test]
+fn test_text_replacer_complex_regex() {
+    let replacer = TextReplacer::builder()
+        .pattern(r"(\w+)@(\w+\.\w+)")
+        .replacement("EMAIL_ADDRESS")
+        .regex(true)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("Contact john@example.com or jane@test.org");
+    assert_eq!(result, "Contact EMAIL_ADDRESS or EMAIL_ADDRESS");
+}
+
+#[test]
+fn test_text_replacer_multiline_text() {
+    let replacer = TextReplacer::builder()
+        .pattern(r"^\s*//.*$")
+        .replacement("")
+        .regex(true)
+        .build()
+        .expect("Failed to build replacer");
+
+    let input = "function test() {\n    // This is a comment\n    return true;\n    // Another comment\n}";
+    let result = replacer.replace(input);
+    
+    // Note: This test depends on how the regex engine handles multiline mode
+    // The actual behavior might need adjustment based on regex flags
+    assert!(result.contains("function test()"));
+    assert!(result.contains("return true;"));
+}
+
+#[test]
+fn test_text_replacer_unicode_text() {
+    let replacer = TextReplacer::builder()
+        .pattern("café")
+        .replacement("coffee")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace("I love café in the morning");
+    assert_eq!(result, "I love coffee in the morning");
+}
+
+#[test]
+fn test_text_replacer_large_text() {
+    let large_text = "word ".repeat(10000);
+    
+    let replacer = TextReplacer::builder()
+        .pattern("word")
+        .replacement("term")
+        .regex(false)
+        .build()
+        .expect("Failed to build replacer");
+
+    let result = replacer.replace(&large_text);
+    assert_eq!(result, "term ".repeat(10000));
+}