JacocoReport Task: Get overall coverage by simply adding submodules files to sourceDirectories and classDirectories?

Tool Version

gradle 5.6.4

java 1.8

jacoco toolVersion 0.8.2

Project Structure

├── build.gradle
├── app
│   ├── build.gradle (1)
│   └── src
├── submodule_1
│   ├── build.gradle (2)
│   └── src
├── submodule_2
│   ├── build.gradle (3)
│   └── src
├── gradle
│   ├── jacoco.gradle
│   └── other_scripts.gradle

Description

(1) imports jacoco.gradle.

(1), (2) and (3) have the following configuration:

    buildTypes {
        debug {
            testCoverageEnabled true
        }
    }

Problem

I want to get an overall coverage, can I just simply include the files of submodules in the properties classDirectories and sourceDirectories, or shell I include them in additionalClassDirs? I don't really understand their difference.

Here is gradle/jacoco.gradle imported by app/build.gradle.

apply plugin: 'jacoco'

def coverageSourceDirs = [
        "${rootDir.absolutePath}/app/src",
        "${rootDir.absolutePath}/submodule_1/src",
        "${rootDir.absolutePath}/submodule_2/src",
]

def coverageClassDirs = [
        fileTree(dir: "${rootDir.absolutePath}/app/build/intermediates/javac/SNMAPP__10009Debug/compileSNMAPP__10009DebugJavaWithJavac/classes", excludes: androidExclusion),
        fileTree(dir: "${rootDir.absolutePath}/submodule_1/build/intermediates/javac/debug/compileDebugJavaWithJavac/classes", excludes: androidExclusion),
        fileTree(dir: "${rootDir.absolutePath}/submodule_2/build/intermediates/javac/debug/compileDebugJavaWithJavac/classes", excludes: androidExclusion),
]

task jacocoTestReport_test(type: JacocoReport) {
    group = "Reporting"
    description = "Generate Jacoco coverage reports runing tests."

    reports {
        xml.enabled = true
        html.enabled = true
        html.destination file("${rootDir.absolutePath}/app/build/reports/jacoco")
    }
    sourceDirectories = files(coverageSourceDirs)
    classDirectories = files(coverageClassDirs)
    executionData = files("${rootDir.absolutePath}/app/build/outputs/code_coverage/SNMAPP__10009DebugAndroidTest/connected/coverage.exec")
}

Solution

Yes, you just need to include the files of submodules in classDirectories and sourceDirectories. By the way, you should include all of test result of your submodules in executionData

def appAndroidTests = fileTree(dir: "${buildDir}/outputs/code_coverage/{your flavor}AndroidTest/connected", includes: ["*.ec"])

executionData = files(
  "${buildDir}/jacoco/test{your flavor}UnitTest.exec",
  "../submodule_1/build/jacoco/test{your flavor}UnitTest.exec",
  "../submodule_2/build/jacoco/test{your flavor}UnitTest.exec",
  appAndroidTests
)