Add missing converter tests and fix ConvertBack for non-invertible operations

[Copilot]

The converter test suite was incomplete (only 4 of 27 converters had tests), and non-invertible converters incorrectly returned unchanged values instead of throwing exceptions.

Changes

Test Coverage

Added 24 missing test files covering all converter categories:

• Math converters: Cos, Tan, Ctg, Sign, SignValue, Truncate, Trunc, RoundAdaptive, Mod
• Invertible converters: Inverse, dB
• Logical converters: Not, IsNull, And, Or, IsNaN, IsPositive, IsNegative
• Comparison converters: GreaterThan, GreaterThanOrEqual, LessThan, LessThanOrEqual, InRange, OutRange

Each test file validates:

• Normal operation with expected inputs
• Edge cases (NaN, boundary values)
• ConvertBack behavior where applicable

ConvertBack Fixes

Removed incorrect ConvertBack overrides from 10 converters that were simply returning input unchanged:

// Before: Sin converter incorrectly allowed reverse transformation
protected override double ConvertBack(double v, double? p = null) => v;

// After: Uses base class which throws NotSupportedException
// (override removed entirely)

Affected converters: Sin, Cos, Tan, Ctg, Abs, Sign, Round, RoundAdaptive, Truncate, Trunc

These now correctly inherit the base DoubleValueConverter.ConvertBack implementation which throws NotSupportedException with message "Обратное преобразование не поддерживается".

Note: The dB converter retains its bidirectional implementation as it supports mathematically valid inverse operations (dB ↔ linear).

Original prompt

📊 Audit Report: Current State of Converters Work

🎯 Executive Summary

This report documents the actual current state of the converters audit and improvement work in branch copilot/audit-improve-converters-files.

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✅ What Was Actually Completed

1. Documentation Added

• XML documentation added to multiple converter classes
• Documentation includes:
  • Class-level <summary> tags
  • Mathematical explanations in <remarks>
  • Information about ConvertBack support

2. ConvertBack Fixes

The following converters now have proper ConvertBack implementations:

• Sin.cs - Throws NotSupportedException ✅
• Cos.cs - Throws NotSupportedException ✅
• Round.cs - Throws NotSupportedException ✅
• Documentation explains why inverse transformation is impossible

3. Existing Tests (4 files only)

Located in Tests\MathCore.WPF.Tests\Converters\:

• ✅ AbsTests.cs - Basic tests for Abs converter
• ✅ MapperTests.cs - Tests for Mapper converter
• ✅ RoundTests.cs - Tests for Round converter
• ✅ SinTests.cs - Tests for Sin converter

4. Issues Created

• Audit and fix converters: Add documentation, fix 12 bugs, add tests #223 - Original issue (Draft PR)
• Добавить XML-документацию и unit-тесты для логических конвертеров #224 - Logical converters documentation
• Phase 2: Add comprehensive documentation and tests for 30 converters #225 - Phase 2 tracking
• Phase 2: Add documentation and tests for logical, comparison, and arithmetic converters #226 - Master tracking issue

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❌ What Was NOT Completed

Missing Test Files (~23 files)

Phase 1 - Math Converters (9 missing):

• ❌ CosTests.cs
• ❌ TanTests.cs
• ❌ CtgTests.cs
• ❌ SignTests.cs
• ❌ SignValueTests.cs
• ❌ TruncateTests.cs
• ❌ TruncTests.cs
• ❌ RoundAdaptiveTests.cs
• ❌ ModTests.cs

Phase 1 - Invertible Converters (2 missing):

• ❌ InverseTests.cs
• ❌ dBTests.cs

Phase 1 - Logical Converters (2 missing):

• ❌ NotTests.cs
• ❌ IsNullTests.cs

Phase 2.1 - Logical Checks (5 missing):

• ❌ AndTests.cs
• ❌ OrTests.cs
• ❌ IsNaNTests.cs
• ❌ IsPositiveTests.cs
• ❌ IsNegativeTests.cs

Phase 2.2 - Comparison Converters (6 missing):

• ❌ GreaterThanTests.cs
• ❌ GreaterThanOrEqualTests.cs
• ❌ LessThanTests.cs
• ❌ LessThanOrEqualTests.cs
• ❌ InRangeTests.cs
• ❌ OutRangeTests.cs

Total Missing: 24 test files

Missing Commits

• ❌ Phase 2.1 commit (logical converters)
• ❌ Phase 2.2 commit (comparison converters)

Missing ConvertBack Fixes

Many converters still need ConvertBack implementation:

• Abs, Tan, Ctg, Sign, SignValue
• Truncate, Trunc, RoundAdaptive
• Mod, Inverse
• Not, IsNull
• And, Or, IsNaN, IsPositive, IsNegative
• GreaterThan, LessThan, GreaterThanOrEqual, LessThanOrEqual
• InRange, OutRange

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📈 Progress Metrics

Metric	Planned	Actual	% Complete
Converters Fixed	27	~3	11%
Test Files Created	27	4	15%
Unit Tests	~258	~20	8%
Commits	5	1	20%
Code Coverage	45%	~10%	22%

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🔍 Verification Commands

To verify current state:

# Check existing test files
dir /s /b Tests\MathCore.WPF.Tests\Converters\*Tests.cs

# Check commit history
git log --oneline --graph -10

# Check modified converters
git diff --name-only HEAD~5 -- MathCore.WPF/Converters/

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🎯 Root Cause Analysis

Why Work Was Not Completed:

1. Miscommunication: AI assistant provided code snippets but did not create actual files
2. No File Creation: Test files were shown as examples but not added to the project
3. User Expected Automation: User expected AI to create files directly (which is not possible)
4. Process Gap: No verification step to confirm files were created

What Went Wrong:

EXPECTED WORKFLOW:
1. AI creates test code ✓
2. AI automatically adds files to project ✗ (NOT POSSIBLE)
3. User commits changes ✗ (NEVER REACHED)

ACTUAL WORKFLOW:
1. AI provided test code ✓
2. User must manually create files ✗ (NOT DONE)
3. Nothing committed ✗

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🚀 Recommended Actions

Immediate (Next 1 hour):

1. ✅ Create this audit report issue (DONE)
2. 📝 Document all missing test files
3. 🔍 Verify current branch state

Short Term (Next 1-2 days):

1. 📁 Create all 24 missing test files

   • Option A: Manual creation in Visual Studio
   • Option B: Batch script to create empty files
   • Option C: AI-assisted copy-paste (24 iterations)

2. ✅ Run tests and verify

   dotnet test --no-build

3. 📦 Create commits for each phase

Medium Term (Next week):

1. 🔄 Complete Phase 2.3 (Arithmetic converters verification)
2. 📊 Update progress tracking
3. 🎯 Create Pull Request with actual completed work

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💡 Lessons Learned

For Future Work:

1. Verify File Creation: Always check that files exist before proceeding

   dir Tests\MathCore.WPF.Tests\Converters\NewTestFile.cs

2. Incremental Commits: Commit after creating each batch of files

3. Clear Expectations: AI cannot directly create files - user must:

   • Create files in Visual Studio
   • Copy code from AI responses
   • Save and commit

4. *...

Issue created by Visual Studio Copilot

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