Verify JaCoCo coverage measurement is functional after issue #26 fix

[Copilot]

Issue #27 reported coverage regression from 49% to 12% despite adding 276 tests. Investigation revealed this was caused by issue #26 (Gradle build failures) preventing JaCoCo report generation.

Changes

• Installed jDisco 1.2.0 dependency - Downloaded from GitHub releases (https://github.com/bedaHovorka/jdisco/releases/download/v1.2.0/jdisco-1.2.0.jar) to Maven local repository to enable builds
• Verified JaCoCo functionality - Generated coverage report showing 44.6% coverage (7,569/16,962 instructions) for 268 tests
• Confirmed configuration correctness - JaCoCo properly measures Kotlin classes in build/classes/kotlin/main

Root Cause

The reported regression was not a JaCoCo configuration issue. The repository currently has 268 tests (267 passing, 1 skipped), not the expected 591 tests from Phase 6. Missing 323 tests explains the coverage gap (44% actual vs 49-62% expected). Repository grafting at commit cb60631 likely lost test history.

Coverage Breakdown

Package	Coverage	Notes
xml	84%	✅ Well tested
util	75%	✅ Well tested
context	69%	✅ Well tested
objects.cells	64%	✅ Adequate
sim	26%	⚠️ Needs tests
gui.*	0%	Untested

JaCoCo measurement is working correctly. No configuration changes required.

Original prompt

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This section details on the original issue you should resolve

<issue_title>🔴 P0: Coverage measurement regression -37% (49% → 12%) despite +276 tests</issue_title>
<issue_description>## Bug Description

Severity: 🔴 CRITICAL (P0)
Status: BLOCKED by #26
Component: JaCoCo integration or test execution
Discovered: 2026-01-10 during test coverage expansion review

Coverage regressed from 49% (Phase 3, 8,625 instructions) to 12% (Phase 6, 2,177 instructions), despite adding 276 new passing tests in Phases 4-6. This is a -37% drop (-5,697 instructions) with +276 tests, which is mathematically impossible unless coverage measurement is broken.

Coverage Trajectory

Phase	Tests	Coverage	Instructions	Change
Baseline	242	45%	7,566	—
Phase 1	293	47%	8,104	+538 ✅
Phase 3	347	49%	8,625	+521 ✅
Phase 5	423	46%	7,874	-751 ⚠️
Phase 6	591	12%	2,177	-5,697 🔴

Impact

• ❌ Cannot verify coverage goals achieved (target: 68%)
• ❌ Cannot determine actual test effectiveness
• ❌ Unknown which packages still need coverage
• ❌ Cannot make data-driven decisions about test expansion
• ❌ Blocks validation of PR Analyze test coverage and create implementation plan for 68% target #23

Root Cause Hypothesis

1. Most likely: 🔴 P0: Gradle test process exits with code 1 despite all tests passing - blocks JaCoCo #26 (Gradle exit code) blocks JaCoCo report generation
2. JaCoCo not instrumenting new test files
3. Integration tests excluded from coverage (missing @Tag("integration-test"))
4. Clean build removes cumulative coverage (not aggregated)
5. Test file placement outside of JaCoCo source set

Investigation Steps (After #26 Fixed)

# 1. Regenerate coverage with clean build
./gradlew clean test jacocoTestReport

# 2. Check if integration tests run during coverage
./gradlew test integrationTest jacocoTestReport

# 3. Compare package-level coverage
# Open: build/reports/jacoco/test/html/index.html
# Check: objects/tracks (should be 85%), objects/paths (should be 49%)

# 4. Verify all 591 tests execute during coverage
./gradlew test --info 2>&1 | grep "tests completed"

# 5. Check JaCoCo exclusion patterns
grep -A 10 "jacocoTestReport" build.gradle.kts

Expected Resolution

After fixing #26, coverage should be:

• Pessimistic estimate: 52-55% (Phases 4-6 add ~1,000 instructions)
• Optimistic estimate: 58-62% (Phases 4-6 add ~2,000 instructions)
• If still 12%, deeper investigation needed

Related Issues

• 🔴 P0: Gradle test process exits with code 1 despite all tests passing - blocks JaCoCo #26 - Gradle test exit code (BLOCKING THIS ISSUE)
• Deeper test, text extension to pass Quality gate at sonar at least 68% #22 - Test coverage expansion goal (68%)
• 2 test classes missing @Tag("integration-test") annotation

Estimated Fix Time

30 minutes after #26 is fixed

References

• BUGS_FOUND.md - BUG-002
• Branch: copilot/increase-test-coverage
  </issue_description>

<agent_instructions>analyse and please provide fix</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes 🔴 P0: Coverage measurement regression -37% (49% → 12%) despite +276 tests #27

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[bedaHovorka]

ok verification done

[bedaHovorka]

fixed by #30