Add JaCoCo branch coverage gate (80% minimum) to Maven build #120

New Issue

marcel · 2026-03-27T18:35:46+01:00

marcel commented

2026-03-27 18:35:46 +01:00

Problem

The backend build has no coverage measurement. There is no JaCoCo plugin configured, no coverage report generated, and the CI pipeline never reports a coverage number. The 80% branch coverage floor we aim for is completely unenforced — we don't even know what the current coverage is.

Why This Matters

Line coverage is a vanity metric. Branch coverage tells you whether your tests actually exercise decision points — the if/else, the switch, the Optional.orElseThrow. Without measuring it, we have no signal when a new service method ships with zero test coverage. A missed branch on an error path is exactly where production bugs hide.

What Needs To Be Done

Add JaCoCo Maven plugin to pom.xml:

<plugin>
  <groupId>org.jacoco</groupId>
  <artifactId>jacoco-maven-plugin</artifactId>
  <executions>
    <execution>
      <id>prepare-agent</id>
      <goals><goal>prepare-agent</goal></goals>
    </execution>
    <execution>
      <id>report</id>
      <phase>verify</phase>
      <goals><goal>report</goal></goals>
    </execution>
    <execution>
      <id>check</id>
      <phase>verify</phase>
      <goals><goal>check</goal></goals>
      <configuration>
        <rules>
          <rule>
            <element>BUNDLE</element>
            <limits>
              <limit>
                <counter>BRANCH</counter>
                <value>COVEREDRATIO</value>
                <minimum>0.80</minimum>
              </limit>
            </limits>
          </rule>
        </rules>
      </configuration>
    </execution>
  </executions>
</plugin>

Run ./mvnw verify to get the current coverage baseline
Exclude generated code and config classes from coverage measurement (DTOs, @Configuration classes)
Upload the JaCoCo XML report as a CI artifact

Acceptance Criteria

./mvnw verify fails if branch coverage drops below 80%
Coverage report uploaded as artifact in CI
Current coverage is ≥ 80% (or a plan exists to close the gap)

## Problem The backend build has no coverage measurement. There is no JaCoCo plugin configured, no coverage report generated, and the CI pipeline never reports a coverage number. The 80% branch coverage floor we aim for is completely unenforced — we don't even know what the current coverage is. ## Why This Matters Line coverage is a vanity metric. Branch coverage tells you whether your tests actually exercise decision points — the `if/else`, the `switch`, the `Optional.orElseThrow`. Without measuring it, we have no signal when a new service method ships with zero test coverage. A missed branch on an error path is exactly where production bugs hide. ## What Needs To Be Done 1. Add JaCoCo Maven plugin to `pom.xml`: ```xml <plugin> <groupId>org.jacoco</groupId> <artifactId>jacoco-maven-plugin</artifactId> <executions> <execution> <id>prepare-agent</id> <goals><goal>prepare-agent</goal></goals> </execution> <execution> <id>report</id> <phase>verify</phase> <goals><goal>report</goal></goals> </execution> <execution> <id>check</id> <phase>verify</phase> <goals><goal>check</goal></goals> <configuration> <rules> <rule> <element>BUNDLE</element> <limits> <limit> <counter>BRANCH</counter> <value>COVEREDRATIO</value> <minimum>0.80</minimum> </limit> </limits> </rule> </rules> </configuration> </execution> </executions> </plugin> ``` 2. Run `./mvnw verify` to get the current coverage baseline 3. Exclude generated code and config classes from coverage measurement (DTOs, `@Configuration` classes) 4. Upload the JaCoCo XML report as a CI artifact ## Acceptance Criteria - [ ] `./mvnw verify` fails if branch coverage drops below 80% - [ ] Coverage report uploaded as artifact in CI - [ ] Current coverage is ≥ 80% (or a plan exists to close the gap)

marcel added the test label 2026-03-27 18:45:07 +01:00

marcel referenced this issue

2026-03-27 18:54:02 +01:00

Add Testcontainers + @DataJpaTest against real PostgreSQL 16 #119

marcel commented

2026-03-27 18:54:10 +01:00

Architect review (@mkeller): ⚠️ The JaCoCo config is correct, but the sequencing matters.

Do #119 (Testcontainers + real PostgreSQL) before adding this gate. If you add an 80% branch coverage floor today against the current mock-heavy test suite, you will either discover the gate immediately fails and disable it in frustration, or you'll find coverage appears artificially high because barely-touched service methods don't contribute meaningful branches. Neither gives useful signal.

Right sequence:

Complete #119 — write real repository and service tests against PostgreSQL
Run ./mvnw verify to get the actual measured baseline
Set the gate at the current baseline (not aspirationally at 80%)
Ratchet it upward deliberately over time

The acceptance criterion "Current coverage is ≥ 80% (or a plan exists to close the gap)" is a bit circular — you need to measure before you can know whether a plan is needed.

**Architect review (@mkeller):** ⚠️ The JaCoCo config is correct, but the sequencing matters. Do #119 (Testcontainers + real PostgreSQL) before adding this gate. If you add an 80% branch coverage floor today against the current mock-heavy test suite, you will either discover the gate immediately fails and disable it in frustration, or you'll find coverage appears artificially high because barely-touched service methods don't contribute meaningful branches. Neither gives useful signal. Right sequence: 1. Complete #119 — write real repository and service tests against PostgreSQL 2. Run `./mvnw verify` to get the actual measured baseline 3. Set the gate at the current baseline (not aspirationally at 80%) 4. Ratchet it upward deliberately over time The acceptance criterion "Current coverage is ≥ 80% (or a plan exists to close the gap)" is a bit circular — you need to measure before you can know whether a plan is needed.

marcel referenced this issue

2026-03-27 18:54:15 +01:00

Add @vitest/coverage-v8 with 80% branch coverage threshold to frontend build #121

marcel commented

2026-03-28 16:29:01 +01:00

Baseline measured: 46.8% branch coverage (265/566 branches covered, excluding DTOs, config classes, model entities, and ErrorCode enum).

Initial gate set at 42% (baseline − 5%) to prevent regression without blocking CI.

Gap to target: 46.8% → 80% = 33.2 percentage points. The main coverage gaps are service error paths (DomainException branches in DocumentService, PersonService, UserService) and the security/permission layer. Each new service test that covers an error path will close this gap.

**Baseline measured: 46.8% branch coverage** (265/566 branches covered, excluding DTOs, config classes, model entities, and ErrorCode enum). Initial gate set at **42%** (baseline − 5%) to prevent regression without blocking CI. Gap to target: 46.8% → 80% = **33.2 percentage points**. The main coverage gaps are service error paths (DomainException branches in DocumentService, PersonService, UserService) and the security/permission layer. Each new service test that covers an error path will close this gap.

marcel referenced this issue from a commit

2026-03-28 17:30:25 +01:00

test(#120): add JaCoCo branch coverage gate to Maven build

marcel referenced this issue

2026-03-28 17:32:02 +01:00

test: complete test suite (#118, #119, #120, #121, #123, #125) #146

marcel referenced this issue

2026-03-28 18:05:08 +01:00

test: improve backend branch coverage (currently 46%) #148

marcel closed this issue

2026-03-29 13:40:25 +02:00

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