Android multi module test dependency

Question

With Android Studio 3.0 / android_gradle_version = '3.0.1' / gradle-4.5

Let's say I have two android modules

module-base
module-a

When I want to access sources from module-base in module-a , I just need to write this in my module-a.gradle

dependencies {
implementation project(path: ':module-base')
}

But, what if I want to access test sources from module-base in test of module-a? Here does not work approach like above

dependencies {
testImplementation project(path: ':module-base')
}

I found lot of advices (few years old) which says something like

    compileTestJava.dependsOn tasks.getByPath(':module-base:testClasses')
    testCompile files(project(':module-base').sourceSets.test.output.classesDir)

or testCompile project(':module-base).sourceSets.test.classes

But no one from mentioned works. There is always something wrong from the compiler point of view :-/

Can you someone help me how to create Android test code dependency between two modules?

Answer 1

Actually I find just workaround for this. Don't use test sources from module-base but use sources from test related module module-testutils which is defined like this

dependencies{
   testImplementation project(':module-testutils')
}

Thus you can share common test code which will be excluded for non-testable apk.

Answer 2

In case anyone else ends up here, one way to accomplish this is to define the target module as a source set. Let's assume test-mdoule is the module we want to import stuff from, we can do it this way:

android {
    sourceSets {
        // non-instrumental test example
        test {
            java.srcDir project(":test-module").file("src/test/java")
        }
        // instrumental test example
        androidTest {
            java.srcDir project(":test-module").file("src/androidTest/java")
        }
    }
}

Reference: https://jonnycaley.medium.com/sharing-test-code-in-a-multi-module-android-project-7ce4de788016