JaCoCo shows 0% coverage, even all tests had passed

问题

1. I have written some test cases under androidTest directory.
2. I am using androidx (testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner")

3. added dependencies:

   androidTestImplementation 'androidx.test:runner:1.1.0'

   androidTestImplementation 'androidx.test:rules:1.1.0'

4. added JaCoCo as dependency, as well.

5. When I run createDebugAndroidTestCoverageReport Gradle task, all the test cases run successfully but coverage is 0% in report

I am guessing that is due to this error:

V/InstrumentationResultParser: Error: Failed to generate Emma/JaCoCo coverage. V/InstrumentationResultParser: INSTRUMENTATION_CODE: -1

回答1:

A custom version of the androidx.test.runner.AndroidJUnitRunner is most likely not required.

But this path here, which you've defined as the debugTree:

"${project.buildDir}/intermediates/classes/debug"

Might meanwhile be something alike:

"${project.buildDir}/intermediates/javac/debug/compileDebugJavaWithJavac/classes"

for example:

build/intermediates/javac/debug/compileDebugJavaWithJavac/classes
build/intermediates/javac/release/compileReleaseJavaWithJavac/classes

If it cannot find the *.class files, the test-coverage will be reported as 0%.

Just browse the build directory to see what the actual path is.

来源：https://stackoverflow.com/questions/55575418/jacoco-shows-0-coverage-even-all-tests-had-passed