LAB 03 – Tests, coverage & analysis parameters

Story: The CTO asks a simple question: "How much of our code is tested?" SonarQube does not run tests – it imports the reports your build produces. Time to wire them in and tune what gets analysed.

Duration	~40 min
You edit	work/bookshelf-py/sonar-project.properties, work/bookshelf-java/pom.xml

flowchart LR
  B[build tool<br/>pytest / Maven] -->|coverage.xml<br/>junit.xml<br/>jacoco.xml| S[scanner]
  SRC[source code] --> S
  S -->|report| SQ[SonarQube<br/>compute engine]

Step 1 – Java: JaCoCo is already wired

Open work/bookshelf-java/pom.xml:

• jacoco-maven-plugin → prepare-agent + report writes target/site/jacoco/jacoco.xml
• sonar.coverage.jacoco.xmlReportPaths tells the scanner where to find it

Look at the project in SonarQube: Coverage ≈ 27 %. Open InventoryReport.java in the Code tab – red/green bars show uncovered/covered lines.

Step 2 – Python: generate the reports

./bin/lab checks-py
ls work/bookshelf-py/reports/

✅ Checkpoint: 5 passed, and coverage.xml, junit.xml exist (plus linter reports – LAB04).

Step 3 – Python: import tests and coverage

In work/bookshelf-py/sonar-project.properties uncomment the LAB03 block:

sonar.tests=tests
sonar.python.coverage.reportPaths=reports/coverage.xml
sonar.python.xunit.reportPath=reports/junit.xml

./bin/lab scan-py

✅ Checkpoint: the scanner log shows Sensor Cobertura Sensor for Python coverage → Parsing report '/usr/src/reports/coverage.xml', and the dashboard shows Coverage ≈ 40 % and Unit Tests: 5.

sonar.sources = production code, sonar.tests = test code. Test files are not counted in lines of code or coverage, and get their own (test) rules.

Step 4 – Scoping the analysis

Property	Effect
sonar.exclusions	files not analysed at all
sonar.coverage.exclusions	analysed, but ignored for coverage
sonar.cpd.exclusions	ignored for duplication detection
sonar.test.inclusions	which files under sonar.tests are tests
sonar.issue.ignore.multicriteria	ignore specific rules on specific files

Task: the team agrees that generated protobuf files (*_pb2.py) must never be analysed, and that orders.py is "not worth testing". Add:

sonar.exclusions=**/*_pb2.py
sonar.coverage.exclusions=bookshelf/orders.py

Re-run ./bin/lab scan-py. How did coverage change? Is that honest? Discuss – then remove the coverage exclusion again.

Where to set parameters (highest priority first): command line -D… → scanner/build file (sonar-project.properties, pom.xml) → project settings in the UI → global settings. Prefer files in Git – they are reviewed and versioned.

Step 5 – What is "new code"?

1. Project Settings → New Code: switch bookshelf-py to Number of days = 30. When is "previous version" better? When reference branch?
2. Make a change and commit it:

```bash cd work/bookshelf-py cat >> bookshelf/orders.py <<'EOF'

def gift_wrap_fee(items): fee = 0 for item in items: if item.get("gift"): fee = fee + 2.5 return fee EOF git commit -qam "Add gift wrap fee" && cd ../.. ./bin/lab checks-py && ./bin/lab scan-py ```

1. Open the New Code tab of the overview. What is the coverage on new code? Why does the quality gate still pass?

Answer

The new function is not tested → coverage on new code is low, but SonarQube ignores coverage and duplication conditions while the new code has **fewer than 20 lines** (to avoid failing on tiny changes). Add a few more untested lines (or lower the threshold in LAB05) and the gate turns red.

Bonus

• Add a test for gift_wrap_fee in tests/test_orders.py, rerun – watch coverage on new code go to 100 %.
• Java: run ./bin/lab scan-java -Dsonar.coverage.exclusions=**/InventoryReport.java – one-off parameters from the command line.

Troubleshooting

Symptom	Likely cause
No report was found for sonar.python.coverage.reportPaths	wrong path, or checks-py not run before the scan
coverage 0 % although the report is found	paths inside the report don't match the analysed files (run tests from the project root)
tests counted as code	sonar.tests missing, or sonar.sources=. without exclusions

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Files for this lab: Think-Cube/sonarqube-labs/labs/LAB03-tests-coverage