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scoverage-maven-plugin

scoverage-maven-plugin is a plugin for Maven that integrates the scoverage code coverage library. Find out more about scoverage.

How to use

mostly used mojos:

check goal compiles classes with instrumentation, runs unit tests and checks coverage,
report goal compiles classes with instrumentation, runs unit tests and generates reports,
integration-check goal compiles classes with instrumentation, runs unit and integration tests and checks coverage,
integration-report goal compiles classes with instrumentation, runs unit and integration tests and generates reports,

additional, sometimes useful, mojos:

test goal compiles classes with instrumentation and runs unit tests,
integration-test goal compiles classes with instrumentation and runs unit and integration tests,
check-only goal only checks coverage using coverage data generated earlier in the build (by test, report, integration-test or integration-report goal).
report-only goal generates reports using coverage data generated earlier in the build (by test, check, integration-test or integration-check goal),
package goal generates artifact file containing instrumented classes (e.g. for testing outside of the Maven build),

internal mojos:

pre-compile and post-compile are internal goals, they configure Maven build in forked scoverage life cycle; don't use them.

Maven generated plugin documentation

Version	Documentation
`2.0.6`	Plugin Info
`1.4.11`	Plugin Info

Prerequisites / limitations

The plugin is compatible with Scala Maven Plugin
- version 3.0.0 or later required
- addScalacArgs and analysisCacheFile configuration parameters cannot be set directly, use project properties addScalacArgs and analysisCacheFile instead.
Starting with version 2.1.0 JDK 17+, Maven 3.6.3 and maven-site-plugin 3.20.0+ are required.
Starting with version 2.0.0 the plugin supports Scala 2.12.8+, 2.13.0+ and 3.2.0+. For Scala 2.12.7 and lower please use version 1.4.11 of the plugin.
The plugin is not thread-safe, so it should not be used in multi-threaded builds.

Scoverage Maven plugin version

This can be set as project property.

<project>
    <properties>
        <scoverage.plugin.version>2.0.6</scoverage.plugin.version>
    </properties>
</project>

Scala version configuration

The plugin automatically loads and configures matching scalac-scoverage-plugin artifact when needed. For this to work the Scala version has to be set. It can be done by defining the scalaVersion plugin configuration parameter or the scala.version project property. Without this setting, the plugin will try to resolve the Scala version from the scala-library dependency of the project. If all the attempts to resolve the Scala version fail, then coverage will not be calculated.

<project>
    <properties>
        <scala.version>2.13.15</scala.version>
    </properties>
</project>

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <scalaVersion>2.13.15</scalaVersion>
                    <!-- other parameters -->
                </configuration>
             </plugin>
        </plugins>
    </build>
</project>

The first method is better because once the property is defined its value can be used in other places of the build file. For example in the scala-library dependency version every Scala build should declare.

<project>
    <dependencies>
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
        </dependency>
    </dependencies>
</project>

Scalac SCoverage plugin version configuration

Maven SCoverage plugin uses by default the latest version of the scalac-scoverage-plugin available on its release day. If newer, better version of scalac-scoverage-plugin is available, it can be used instead. It can be configured by defining the scalacPluginVersion plugin configuration parameter or the scoverage.scalacPluginVersion project property.

<project>
    <properties>
        <scoverage.scalacPluginVersion>2.2.1</scoverage.scalacPluginVersion>
    </properties>
</project>

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <scalacPluginVersion>2.2.1</scalacPluginVersion>
                    <!-- other parameters -->
                </configuration>
             </plugin>
        </plugins>
    </build>
</project>

Integration tests coverage check and reports

integration-check and integration-report mojos are similar to check and report mojos, but they execute forked scoverage life cycle up to verify phase (integration tests are usually executed in integration-test phase).

Aggregated reports for multi-module projects

There is no separate mojo for aggregated reports, there is aggregate parameter. To additionally generate aggregated SCoverage report for root module, when generating regular reports, set aggregate parameter value to true. It works only in multimodule projects, the aggregated report will be generated in the current execution root.

It can be configured by defining the aggregate plugin configuration parameter or the scoverage.aggregate project property.

<project>
    <properties>
        <scoverage.aggregate>true</scoverage.aggregate>
    </properties>
</project>

in build/plugins or build/pluginManagement section when running reports directly from console (e.g. mvn scoverage:report)

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <aggregate>true</aggregate>
                </configuration>
             </plugin>
        </plugins>
    </build>
</project>

or in reporting/plugins section when adding report to Maven generated site

<project>
    <reporting>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <aggregate>true</aggregate>
                </configuration>
             </plugin>
        </plugins>
    </reporting>
</project>

Since version 1.4.0-M5 it's possible to generate aggregated report only, without generating reports for individual modules. For large projects it can decrease build time significantly.

To generate only aggregated SCoverage report, set aggregateOnly parameter value to true. It works only in multimodule projects.

It can be configured by defining the aggregateOnly plugin configuration parameter or the scoverage.aggregateOnly project property.

<project>
    <properties>
        <scoverage.aggregateOnly>true</scoverage.aggregateOnly>
    </properties>
</project>

in build/plugins or build/pluginManagement section when running reports directly from console (e.g. mvn scoverage:report)

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <aggregateOnly>true</aggregateOnly>
                </configuration>
             </plugin>
        </plugins>
    </build>
</project>

or in reporting/plugins section when adding report to Maven generated site

<project>
    <reporting>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <aggregateOnly>true</aggregateOnly>
                </configuration>
             </plugin>
        </plugins>
    </reporting>
</project>

Adding SCoverage report to site

Add the plugin to reporting section of your project and configure it to generate one of reporting mojos. By default, Maven executes all plugin's reporting mojos, but the SCoverage plugin has three such mojos, and it does not make sense to execute them all because every executed report will overwrite the previous one. Configure one of them depending on your case.

<project>
    <reporting>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <reportSets>
                    <reportSet>
                        <reports>
                            <report>report</report>
                            <!-- or <report>integration-report</report> -->
                            <!-- or <report>report-only</report> -->
                        </reports>
                    </reportSet>
                </reportSets>
            </plugin>
        </plugins>
    </reporting>
</project>

Which reporting mojo should be selected:

Reporting mojo	When
report	When not using integration tests (most cases)
integration-report	When using integration tests
report-only	When coverage data was already generated (usually by check or integration-check mojo)

Customizing code instrumentation

If you want to customize plugin's configuration parameters used by compilation supporting part of the plugin, do it in 'plugins' or 'pluginManagement' section:

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <highlighting>true</highlighting>
                    <!-- example configuration for Play! Framework 2.x project -->
                    <excludedPackages>views.html.*</excludedPackages> 
                    <excludedFiles>.*?routes_(routing|reverseRouting)</excludedFiles>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Read SBT SCoverage Plugin documentation for more information about excludedPackages and excludedFiles.

File and package exclusions are supported for Scala 2, Scala [3.3.4-3.4.0) and 3.4.2+.

Checking minimum test coverage level

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <minimumCoverage>95</minimumCoverage>
                    <minimumCoverageBranchTotal>90</minimumCoverageBranchTotal>
                    <minimumCoverageStmtPerPackage>90</minimumCoverageStmtPerPackage>
                    <minimumCoverageBranchPerPackage>85</minimumCoverageBranchPerPackage>
                    <minimumCoverageStmtPerFile>85</minimumCoverageStmtPerFile>
                    <minimumCoverageBranchPerFile>80</minimumCoverageBranchPerFile>
                    <failOnMinimumCoverage>true</failOnMinimumCoverage>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>check</goal> <!-- or integration-check -->
                        </goals>
                    </execution>
                </executions>
             </plugin>
        </plugins>
    </build>
</project>

Run mvn scoverage:check to perform the check. See below if you want to use mvn verify to perform the check.

Read SBT SCoverage Plugin documentation for more information.

Checking minimum test coverage level AND adding report to site

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <minimumCoverage>80</minimumCoverage>
                    <failOnMinimumCoverage>true</failOnMinimumCoverage>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>check</goal> <!-- or integration-check -->
                        </goals>
                    </execution>
                </executions>
             </plugin>
        </plugins>
    </build>

    <reporting>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <reportSets>
                    <reportSet>
                        <reports>
                            <report>report-only</report>
                        </reports>
                    </reportSet>
                </reportSets>
            </plugin>
        </plugins>
    </reporting>
</project>

Run mvn scoverage:check to perform the check and mvn scoverage:report to generate the report.

Checking minimum test coverage level automatically

If you want mvn verify and mvn install to check the coverage level, you have to change your POM so that SCoverage takes over running all the tests.

The reason for this is that SCoverage instruments classes during compilation and writes them to disk. We don't want to accidentally deploy these instrumented classes, so SCoverage keeps them separate. SCoverage does this by forking the current Maven build and running it again, while performing instrumentation. In a normal setup this causes the tests to be run twice: once in the outer run with the original classes and once in the SCoverage-forked run with the instrumented classes.

Since version 1.4.0-M5 it's possible to make the tests run only once. You have to configure your pom to turn off testing in the outer run and tell SCoverage to run all tests in the forked run.

This example shows the required configuration:

<project>
    <properties>
        <skipTests>true</skipTests> <!-- disable surefire and failsafe tests -->
    </properties>
...
    <build>
        <plugins>
            <plugin>
                <groupId>org.scoverage</groupId>
                <artifactId>scoverage-maven-plugin</artifactId>
                <version>${scoverage.plugin.version}</version>
                <configuration>
                    <minimumCoverage>80</minimumCoverage>
                    <failOnMinimumCoverage>true</failOnMinimumCoverage>

                    <!-- enable surefire and failsafe tests in SCoverage -->
                    <additionalForkedProjectProperties>skipTests=false</additionalForkedProjectProperties>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>check</goal> <!-- or integration-check -->
                        </goals>
                        <phase>prepare-package</phase> <!-- or any other phase -->
                    </execution>
                </executions>
             </plugin>
        </plugins>
    </build>
</project>

Run mvn clean verify or mvn clean install to run the tests with coverage and all other static analysis you have configured.

If you want to set multiple properties from within <additionalForkedProjectProperties>, for instance because you want to disable other plugins from running twice, you can separate them with a semicolon:

<additionalForkedProjectProperties>skipTests=false;skip.scalafmt=false</additionalForkedProjectProperties>

Examples

There are many example projects in integration tests directory. To run them, execute mvn integration-test. To execute only one of them, execute mvn integration-test -Dinvoker.test=test_aggregate, where test_aggregate is the name of the directory with the example project.

Also, there are many example projects for older versions of the plugin in a separate repo. Go to one of them and run mvn site.

Development

Snapshot deployment

A new snapshot is deployed to sonatype on each commit merged to main branch. See snapshot.yml workflow for details.

New release deployment

Prerequisites

Set sonatype credentials in ~/.m2/settings.xml:

<settings>
  <servers>
    <server>
      <id>central</id>
      <username>sonatype-username-goes-here</username>
      <password>sonatype-password-goes-here</password>
    </server>
  </servers>
</settings>

Make sure you have proper pgp keys set up. See Maven Central Guide for details.

Steps

Run mvn -Darguments="-Dmaven.test.skip=true" -B release:clean release:prepare release:perform -P release.
Wait ~ 8 hours for sync to maven central.
Check jars are available in maven central https://search.maven.org/artifact/org.scoverage/scoverage-maven-plugin and GH label in README is updated.
Checkout new tag, e.g. git checkout scoverage-maven-plugin-2.0.6.
Generate site docs with mvn clean site -P publicsite and check that all required docs are generated in ./target/site.
Checkout gh-pages branch, e.g. git checkout gh-pages.
Copy generated site to new directory named as version number, e.g. cp -r ./target/site ./2.0.6, commit and push.
Wait several seconds for the docs to be published and verify, e.g. https://scoverage.github.io/scoverage-maven-plugin/2.0.6/check-mojo.html.
Checkout main branch, e.g. git checkout main.
Update versions in README, e.g. sed -i 's/2.0.3/2.0.6/g' README.md, commit and push.
Create new Release on GitHub.

This process will be fully or partially automated in the future.

License

This software is licensed under the Apache 2 license, quoted below.

Copyright 2014-2024 Grzegorz Slowikowski

Licensed under the Apache License, Version 2.0 (the "License"); you may not
use this file except in compliance with the License. You may obtain a copy of
the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations under
the License.