Add comprehensive migration status report

Co-authored-by: tig <[email protected]>

Tests/MIGRATION_STATUS.md

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+# Test Migration to UnitTests.Parallelizable - Status Report
+
+## Executive Summary
+
+**Current Status** (Commit d4fd965):
+- **119 tests successfully migrated** to UnitTests.Parallelizable
+- **9,476 tests passing** in Parallelizable (up from 9,357 baseline)
+- **Migration rate: 8.2%** of original 1,446 tests in UnitTests
+- **check-duplicates workflow**: ✅ Passing
+- **All tests**: ✅ Passing
+
+## Migration Breakdown
+
+### Successfully Migrated (119 tests)
+
+#### Pure Unit Tests (26 tests - No driver needed)
+1. **StackExtensionsTests.cs** - 10 tests for Stack<T> extensions
+2. **TabTests.cs** - 1 constructor test  
+3. **AnsiMouseParserTests.cs** - 14 ANSI mouse parsing tests
+4. **Dim.FillTests.cs** - 1 test (merged with existing)
+
+#### Refactored Tests (93 tests - Using local FakeDriver)
+
+**TextFormatterTests.cs** - 10 Draw methods refactored:
+1. Draw_Horizontal_Centered - 11 test cases
+2. Draw_Horizontal_Justified - 11 test cases
+3. Draw_Horizontal_Left - 9 test cases
+4. Draw_Horizontal_Right - 8 test cases  
+5. Draw_Horizontal_RightLeft_BottomTop - 11 test cases
+6. Draw_Horizontal_RightLeft_TopBottom - 11 test cases
+7. Draw_Vertical_BottomTop_LeftRight - 11 test cases
+8. Draw_Vertical_BottomTop_RightLeft - 11 test cases
+9. Draw_Vertical_TopBottom_LeftRight - 3 test cases
+10. Draw_Vertical_TopBottom_LeftRight_Top - 8 test cases
+
+**Refactoring Pattern Used:**
+```csharp
+public void TestMethod (params)
+{
+    // Create local driver instance
+    var factory = new FakeDriverFactory ();
+    var driver = factory.Create ();
+    driver.SetBufferSize (width, height);
+    
+    // Pass driver explicitly to methods
+    textFormatter.Draw (rect, attr1, attr2, driver: driver);
+    
+    // Extract and assert results
+    string actual = GetDriverContents (driver, width, height);
+    Assert.Equal (expected, actual);
+}
+```
+
+## Remaining Work
+
+### TextFormatterTests.cs (8 tests remaining)
+
+**Status Analysis:**
+
+1. **Draw_Vertical_TopBottom_LeftRight_Middle** 
+   - **Can migrate**: Yes, with helper enhancement
+   - **Complexity**: Returns Rectangle, validates Y position
+   - **Action needed**: Enhance helper to return position info
+
+2. **Draw_Vertical_Bottom_Horizontal_Right**
+   - **Can migrate**: Yes, with helper enhancement  
+   - **Complexity**: Returns Rectangle, validates Y position
+   - **Action needed**: Same as above
+
+3. **Draw_Text_Justification**
+   - **Can migrate**: Yes
+   - **Complexity**: Multi-parameter test
+   - **Action needed**: Standard refactoring pattern
+
+4. **Justify_Horizontal** 
+   - **Can migrate**: Yes
+   - **Complexity**: Standard Draw test
+   - **Action needed**: Standard refactoring pattern
+
+5. **FillRemaining_True_False**
+   - **Can migrate**: Need investigation
+   - **Complexity**: May modify state beyond driver
+   - **Action needed**: Review implementation
+
+6. **UICatalog_AboutBox_Text**
+   - **Can migrate**: Need investigation  
+   - **Complexity**: May load external resources
+   - **Action needed**: Review dependencies
+
+7. **FormatAndGetSize_Returns_Correct_Size**
+   - **Can migrate**: Need investigation
+   - **Complexity**: May require specific driver capabilities
+   - **Action needed**: Review method signature
+
+8. **FormatAndGetSize_WordWrap_False_Returns_Correct_Size**
+   - **Can migrate**: Need investigation
+   - **Complexity**: May require specific driver capabilities
+   - **Action needed**: Review method signature
+
+### Other Files with SetupFakeDriver (34 files)
+
+**Files requiring systematic review:**
+
+1. CursorTests.cs
+2. FakeDriverTests.cs  
+3. LineCanvasTests.cs
+4. RulerTests.cs
+5. AdornmentTests.cs
+6. BorderTests.cs
+7. MarginTests.cs
+8. PaddingTests.cs
+9. ShadowStyleTests.cs
+10. AllViewsDrawTests.cs
+11. ClearViewportTests.cs
+12. ClipTests.cs
+13. DrawTests.cs
+14. TransparentTests.cs
+15. LayoutTests.cs
+16. Pos.CombineTests.cs
+17. NavigationTests.cs
+18. TextTests.cs
+19. AllViewsTests.cs
+20. ButtonTests.cs
+21. CheckBoxTests.cs
+22. ColorPickerTests.cs
+23. DateFieldTests.cs
+24. LabelTests.cs
+25. RadioGroupTests.cs
+26. ScrollBarTests.cs
+27. ScrollSliderTests.cs
+28. TabViewTests.cs
+29. TableViewTests.cs
+30. TextFieldTests.cs
+31. ToplevelTests.cs
+32. TreeTableSourceTests.cs
+33. TreeViewTests.cs
+34. SetupFakeDriverAttribute.cs (infrastructure)
+
+**For each file, need to determine:**
+- Which tests use methods that accept driver parameters → Migratable
+- Which tests require View hierarchy/Application context → Likely non-migratable
+- Which tests modify global state → Non-migratable
+
+## Non-Migratable Tests (TBD - Requires detailed analysis)
+
+**Common reasons tests CANNOT be migrated:**
+
+1. **Requires Application.Init()** - Tests that need event loop, application context
+2. **Tests View hierarchy** - Tests that rely on View parent/child relationships requiring Application
+3. **Modifies ConfigurationManager** - Tests that change global configuration state
+4. **Requires specific driver features** - Tests that depend on platform-specific driver behavior
+5. **Integration tests** - Tests validating multiple components together with Application context
+
+## Recommendations
+
+1. **Complete TextFormatterTests migration** - 4-6 tests clearly migratable
+2. **Systematic file-by-file review** - Categorize each of the 34 remaining files
+3. **Document non-migratable** - For each test that cannot be migrated, document specific reason
+4. **Consider test refactoring** - Some integration tests could be split into unit + integration parts
+5. **Update guidelines** - Document patterns for writing parallelizable tests
+
+## Technical Notes
+
+### Why Some Tests Must Remain in UnitTests
+
+Many tests in UnitTests are **correctly placed integration tests** that should NOT be parallelized:
+
+- They test View behavior within Application context
+- They validate event handling through Application.MainLoop
+- They test ConfigurationManager integration
+- They verify driver-specific platform behavior
+- They test complex component interactions
+
+These are valuable integration tests and should remain in UnitTests.
+
+### Pattern for Future Test Development
+
+**New tests should default to UnitTests.Parallelizable unless they:**
+1. Require Application.Init()
+2. Test View hierarchy interactions
+3. Modify global state (ConfigurationManager, Application properties)
+4. Are explicitly integration tests
+