[JAVA] How to get coverage of Android Instrumented Tests [Do your best]

Introduction

This time, I will get coverage with Android Instrumented Tests, so make a note of it. First, when unit testing with Android Studio There was talk of using Robolectric to test Android-dependent parts on the JVM as well. Due to various reasons, I ended up writing the previous test Android Test.

I didn't know anything about Android development for the first time, so I had a good idea to investigate various things.

Strategy 1: Use "createDebugCoverageReport".

• I wrote down how to use it here. https://qiita.com/supergamaspecial/items/505bd8e8c97c30bc9e59 This seemed to be the easiest, so I measured the coverage with this for the time being, but there were some problems (forgive the excuses of lack of knowledge and lack of time).

1. I couldn't change the version of Jacoco

The problem with this is that I couldn't get coverage for C0C1 because the version of Jacoco was old. Honestly, I don't think that the coverage of C0C1 is just numbers and it takes time to be honest. There is no such thing as "the higher the coverage, the higher the quality of the source code".

Well, if I was told to set it to 100, I had no choice but to do it, so I investigated various things. I don't write the test code to make it 100%, but give it to Jacoco 0.8.0 or higher. I saw the article saying that if you upgrade to Jacoco 0.8.0 version, it will improve C0C1 coverage. However, I couldn't change the version of Jacoco referenced in createDebugCoverageReport.

2. Exclusion settings cannot be made

This may be due to lack of study, but I couldn't set exclusions in createDebugCoverageReport. I did a lot of research, but I couldn't do it, so I can't help it.

From the viewpoints 1 and 2 above, we abandon Strategy 1 and move on to Strategy 2.

Strategy 2: "jacoco Test Report"

How to write your own task to get coverage in Gradle. With this, I was able to solve 1 and 2 of Strategy 1.

jacoco {
    toolVersion = "0.8.3"
}
task jacocoTestReport(type: JacocoReport, dependsOn: "connectedDebugAndroidTest") {
    group = "Reporting"
    description = "Generate Jacoco coverage reports"

    // exclude auto-generated classes and tests
    def fileFilter = ['**/R.class',
                      '**/R$*.class',
                      '**/R.styleable',
                      '**/R$*.styleable',
                      '**/BuildConfig.*',
                      '**/Manifest*.*',
                      '**/*IScript*.*',
                      'android/**/*.*',
                      'androidx/**/*.*',
                      '**/*_Impl*',
                      '**/*_Factory*',
                      '**/*_MembersInjector*',
                      '**/*Fake*']

    def debugTree = fileTree(dir:
            "${project.buildDir}/intermediates/javac/debug", excludes: fileFilter)
    def mainSrc = "${project.projectDir}/src/main/java"

    sourceDirectories = files([mainSrc])
    classDirectories = files([debugTree])

    executionData = fileTree(dir: project.projectDir, includes:
            ['**/*.exec', '**/*.ec'])

    reports {
        xml.enabled = true
        xml.destination = "${buildDir}/jacocoTestReport.xml"
        csv.enabled = false
        html.enabled = true
        html.destination = "${buildDir}/reports/jacoco"
    }
}

I was able to specify the version of Jacoco and set exclusions like this, Let's use this one in the future.

Bye bye