Code Coverage Plugin

[paulkagiri]

Code Coverage Plugin

Intro

• Code coverage is a software metric used to measure how many lines of our code are executed during automated tests.

• JaCoCo is a free Java code coverage tool and the JaCoCo plugin provides code coverage metrics for Java code via integration with JaCoCo.

Why

In order to generate JaCoCo unit test coverage reports for Android projects you need to create JacocoReport tasks and configure them by providing paths to source code, execution data and compiled classes. It's not straightforward since Android projects can have different flavors and build types thus requiring additional paths to be set. This plugin configures these JacocoReport tasks automatically.

Usage

plugins {
    ...
    id 'com.gradle.plugin-publish' version '0.14.0' // or whatever version is most recent
}

codeCoverageReport{
    html.enabled = true // by default it's true
    xml.enabled = true // by default it's true
    csv.enabled = true // by default it's false

    unitTests.enabled = true // whether code coverage tasks for unit tests will be generated
    androidTests.enabled = true // whether code coverage tasks for instrumentation tests will be generated

    excludeFlavors = [''] // the product flavors to exclude when generating the code coverage tasks

    excludeClasses = [''] // additional classes to exclude - most are already catered for

    destination = '/some/other/directory' // if you want to configure a custom path to save the code coverage reports, by default your report gets saved in `[project]/build/jacoco/{flavor}{build type}{project}{test type}CoverageReport`

    includeNoLocationClasses = true // To include Robolectric tests in the Jacoco report this needs to be true
}

android {
    buildTypes {
        debug {
            testCoverageEnabled true // this instructs the plugin to generate code coverage reports for this build type
            ...
        }
        release {
            testCoverageEnabled false // this instructs the plugin to NOT generate code coverage reports for this build type
            ...
        }
    }
    ...
    productFlavors {
        local {}
        dist {}
    }
}

The above configuration creates a JacocoReport task for each variant in the form of {flavor}{build type}{project}{test type}CoverageReport

distDebugAppAndroidTestCoverageReport
distDebugAppUnitTestCoverageReport
localDebugAppAndroidTestCoverageReport
localDebugAppUnitTestCoverageReport

By default these are the excluded classes under Constants

[AdamBJohnsonx]

We should have a description indicating what this does, precisely, in the PR description, and links to the documentation of the features used in the code comments, so future authors can have a starting place to go when looking at this code.

[shahzaibj]

An overall comment, was there a specific reason for using kotlin here?

I mean its nice, but I think we also need to get the team onboarded with kotlin as well.

[shahzaibj]

How would this plugin work on Non-Android gradle modules such as common4j or broker4j? Have we tested it?

[paulkagiri]

An overall comment, was there a specific reason for using kotlin here?

I mean its nice, but I think we also need to get the team onboarded with kotlin as well.

I agree with you, will arrange a brownbag on Kotlin

[paulkagiri]

How would this plugin work on Non-Android gradle modules such as common4j or broker4j? Have we tested it?

Non-Android projects support is being added

[paulkagiri]

How would this plugin work on Non-Android gradle modules such as common4j or broker4j? Have we tested it?

The support for Java projects is now available

[AdamBJohnsonx]

Minor comments. If it works, I'm for it.

[shahzaibj]

Were we able to verify that just running the tests doesn't run coverage? (basically only code coverage specific gradle tasks will run the coverage)

[shahzaibj]

It looks fine to me. I think we just need to see it working e2e now.

[paulkagiri]

Cool, I will go ahead and merge this in, thanks @AdamBJohnsonx & @shahzaibj

[paulkagiri]

Were we able to verify that just running the tests doesn't run coverage? (basically only code coverage specific gradle tasks will run the coverage)

Yeah, these changes made that possible - c1145c5