Add JaCoCo code-coverage reporting

[philipwhiuk]

See https://www.eclemma.org/jacoco/ for details

[chrjohn]

Thanks @philipwhiuk
I assume this needs to be integrated into some kind of github action?

[philipwhiuk]

Probably - I'll take a look at doing that for here (we use a separate build system internally so I haven't looked at it).

[the-thing]

This change is correct. I was doing integration with github actions + coverage recently in another project. Later it might want to exclude some things from the report e.g.

 <configuration>
     <excludes>
         <exclude>org/quickfixj/dictgenerator/**</exclude>
     </excludes>
 </configuration>

Next steps.

1. Modify surefire plugin (argline is important)

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>${maven.surefire.plugin.version}</version>
    <configuration>
        <argLine>@{argLine} -Dfile.encoding=${project.build.sourceEncoding}</argLine>
    </configuration>
</plugin>

2. Generate token in CodeCov, Coveralls etc.

3. Add task to upload - here CodeCov.

test-coverage:
  runs-on: ubuntu-latest
  name: Run tests and upload coverage
  steps:
    - uses: actions/checkout@v7
    - name: Set up JDK
      uses: actions/setup-java@v5
      with:
        distribution: 'temurin'
        java-version: 17
        cache: 'maven'
    - name: Test with Maven
      run: <QUICKFIX BUILD STRING>
    - name: Upload coverage reports to Codecov
      uses: codecov/codecov-action@v7
      with:
        token: ${{ secrets.CODECOV_TOKEN }}
        slug: quickfix-j/quickfixj
```

[chrjohn]

@the-thing @philipwhiuk
Thank you for this. I compiled your information into #1285 .