Daily Test Coverage Improver - Fix PermutationTests Incomplete Assertions

[github-actions]

Summary

Fixed incomplete test assertions in PermutationTests.fs that were preventing proper test execution and leaving critical error handling code paths uncovered. All 21 throws<> assertions were missing the required message parameter, causing them to compile with warnings but never actually validate exception throwing behavior.

Problems Found

Test Code Bug: The throws<'ex> helper function in ExpectoStyle.fs requires two parameters:

let throws<'ex when 'ex :> exn> (action: unit -> unit) (message: string)

However, all 21 calls to throws<> in PermutationTests.fs were only providing the action parameter, which resulted in:

1. 14 FS0193 compiler warnings: "This expression is a function value, i.e. is missing arguments. Its type is string -> unit."
2. Tests never executed: The tests compiled to partial functions that were never invoked
3. Uncovered error paths: Critical validation logic in Permutation.fs remained untested

Uncovered Lines Before Fix:

• Line 43 (Permutation.fs): Out-of-range index error in ofFreshArray - "Permutation array contains out-of-range index."
• Line 45 (Permutation.fs): Duplicate indices error in ofFreshArray - "Permutation array contains duplicate indices."
• Line 51 (Permutation.fs): Permutation function bounds checking - "Permutation function called with out-of-range index."

Actions Taken

1. Fixed all 21 throws<> assertions by adding descriptive message parameters
2. Eliminated all 14 compiler warnings (FS0193)
3. Verified tests execute correctly and validate exception behavior
4. Re-ran coverage to confirm error paths are now covered

Example Fix:

Before:

throws<ArgumentException>(fun () -> Permutation.ofFreshArray arr |> ignore)

After:

throws<ArgumentException>(fun () -> Permutation.ofFreshArray arr |> ignore) "should throw on duplicate indices"

Test Coverage Results

Metric	Before	After	Change
Overall Line Coverage	77.33% (1583/2047)	77.47% (1586/2047)	+0.14% (+3 lines)
PermutationModule Coverage	93.93% (62/66)	100.00% (66/66)	+6.07% (+4 lines)
ofFreshArray@49 Coverage	66.66% (4/6)	100.00% (6/6)	+33.34% (+2 lines)
Compiler Warnings	14 FS0193 warnings	0 warnings	-14 warnings
Total Tests	1347 passing	1347 passing	No change

Replicating the Test Coverage Measurements

Prerequisites

cd /path/to/FsMath

Before Coverage (from main branch)

git checkout main
dotnet restore
dotnet build

# Note the 14 FS0193 warnings about missing function arguments
# in PermutationTests.fs during build

# Run tests with coverage
dotnet test tests/FsMath.Tests/FsMath.Tests.fsproj \
  --collect:"XPlat Code Coverage" \
  --results-directory ./coverage-before \
  -- DataCollectionRunSettings.DataCollectors.DataCollector.Configuration.Format=cobertura

# Check PermutationModule coverage: 93.93%
# Check warnings: 14 FS0193 warnings

After Coverage (from this branch)

git checkout daily-test-improver-permutation-throws-fix-20251013-cb94c0deea9e499b
dotnet restore
dotnet build

# Note: 0 FS0193 warnings now!

# Run tests with coverage
dotnet test tests/FsMath.Tests/FsMath.Tests.fsproj \
  --collect:"XPlat Code Coverage" \
  --results-directory ./coverage-after \
  -- DataCollectionRunSettings.DataCollectors.DataCollector.Configuration.Format=cobertura

# Check PermutationModule coverage: 100.00%
# Check warnings: 0 warnings

Display Coverage Comparison

python3 << 'PYTHON_EOF'
import xml.etree.ElementTree as ET
import glob

# Parse before and after coverage reports
before_file = glob.glob('./coverage-before/*/coverage.cobertura.xml')[0]
after_file = glob.glob('./coverage-after/*/coverage.cobertura.xml')[0]

tree_before = ET.parse(before_file)
tree_after = ET.parse(after_file)

# Overall coverage
before_rate = float(tree_before.getroot().get('line-rate', 0)) * 100
after_rate = float(tree_after.getroot().get('line-rate', 0)) * 100
print(f"Overall: {before_rate:.2f}% → {after_rate:.2f}% (+{after_rate - before_rate:.2f}%)")

# PermutationModule coverage
for cls in tree_after.getroot().iter('class'):
    if cls.get('name') == 'FsMath.PermutationModule':
        rate = float(cls.get('line-rate', 0)) * 100
        print(f"PermutationModule: {rate:.2f}%")
PYTHON_EOF

Verify Warnings Fixed

# On main branch (before)
dotnet build tests/FsMath.Tests/FsMath.Tests.fsproj 2>&1 | grep -c "FS0193"
# Should output: 14

# On this branch (after)
dotnet build tests/FsMath.Tests/FsMath.Tests.fsproj 2>&1 | grep -c "FS0193"
# Should output: 0

Future Areas for Improvement

Based on remaining coverage gaps in the codebase:

1. SpanPrimitives.fs - 0% coverage (366 lines) - Inline Span functions (quotation technique doesn't work with Span/byref)
2. SpanMath.fs - 0% coverage (160 lines) - Inline span-based math
3. SIMDUtils.fs - 0% coverage (206 lines) - Inline SIMD operations
4. SVD.fs - 85.9% coverage (72 uncovered lines) - Complex SVD algorithm edge cases
5. Matrix.fs - 88.6% coverage (82 uncovered lines) - Currently being addressed in PR Daily Test Coverage Improver - Matrix Edge Case Tests #67

Note: This PR demonstrates the importance of carefully reviewing compiler warnings and ensuring test assertions are properly configured. The fix was straightforward but had significant impact on coverage and code quality.

Significance

This fix is particularly important because:

1. Security/Correctness: The uncovered error paths validate critical input constraints (array bounds, duplicate detection)
2. Test Quality: Tests appeared to exist but weren't actually executing validation logic
3. Maintainability: Compiler warnings now eliminated, making future issues more visible
4. Coverage Accuracy: Previous coverage numbers understated actual test gaps

---

Commands Executed

Analysis

# Read coverage report
cat coverage-steps.log
python3 coverage_analysis.py  # Analyzed coverage for uncovered areas

# Check PermutationModule coverage details
python3 find_uncovered_permutation_lines.py

Git Operations

git checkout -b daily-test-improver-permutation-throws-fix-20251013-cb94c0deea9e499b
# Made 21 edits to PermutationTests.fs
git add tests/FsMath.Tests/PermutationTests.fs
git commit -m "Fix PermutationTests: Add missing message parameters..."

Build and Test

# Build with 0 warnings (previously 14)
dotnet build tests/FsMath.Tests/FsMath.Tests.fsproj

# Run tests - all pass
dotnet test tests/FsMath.Tests/FsMath.Tests.fsproj --no-build
# Result: Passed: 1347, Skipped: 8

Coverage Measurement

# Original coverage (from workflow)
# Already in ./coverage/coverage.cobertura.xml
# PermutationModule: 93.93%

# New coverage
dotnet test tests/FsMath.Tests/FsMath.Tests.fsproj \
  --no-build \
  --collect:"XPlat Code Coverage" \
  --results-directory ./coverage-new \
  -- DataCollectionRunSettings.DataCollectors.DataCollector.Configuration.Format=cobertura

# Comparison
python3 compare_permutation_coverage.py
# PermutationModule: 100.00% (+6.07%)

Web Searches Performed

None - the issue was identified through coverage analysis and examination of compiler warnings.

Web Pages Fetched

None - all work done through local code analysis.

---

🤖 Generated with Claude Code by Daily Test Coverage Improver

Co-Authored-By: Claude noreply@anthropic.com

AI generated by Daily Test Coverage Improver

AI generated by Daily Test Coverage Improver

[github-actions]

📊 Code Coverage Report

Summary

Package	Line Rate	Branch Rate	Complexity	Health
FsMath	77%	49%	4409	➖
FsMath	77%	49%	4409	➖
Summary	77% (3072 / 3992)	49% (4260 / 8686)	8818	➖

📈 Coverage Analysis

🟡 Good Coverage Your code coverage is above 60%. Consider adding more tests to reach 80%.

🎯 Coverage Goals

• Target: 80% line coverage
• Minimum: 60% line coverage
• Current: 77% line coverage

📋 What These Numbers Mean

• Line Rate: Percentage of code lines that were executed during tests
• Branch Rate: Percentage of code branches (if/else, switch cases) that were tested
• Health: Overall assessment combining line and branch coverage

🔗 Detailed Reports

📋 Download Full Coverage Report - Check the 'coverage-report' artifact for detailed HTML coverage report

---

Coverage report generated on 2025-10-13 at 15:50:00 UTC