RobolectricDetector.android.kt
/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.compose.ui.test.junit4
import androidx.test.ext.junit.runners.AndroidJUnit4
import org.junit.runner.Description
import org.junit.runner.RunWith
internal object RobolectricDetector {
private val RobolectricTestRunnerClassName = "org.robolectric.RobolectricTestRunner"
private val RobolectricParameterizedTestRunnerClassName =
"org.robolectric.ParameterizedRobolectricTestRunner"
private val AndroidJUnit4ClassName =
"androidx.test.internal.runner.junit4.AndroidJUnit4ClassRunner"
private val RobolectricTestRunners = listOf(
RobolectricTestRunnerClassName,
RobolectricParameterizedTestRunnerClassName
).mapNotNull {
try {
Class.forName(it)
} catch (_: ClassNotFoundException) {
null
}
}
internal fun usesRobolectricTestRunner(description: Description): Boolean {
val testRunner = description.testClass?.getAnnotation(RunWith::class.java)?.value?.java
?: return false
return testRunner.isRobolectricRunner || testRunner.usesRobolectricRunner
}
/**
* Returns if this test runner delegates to a Robolectric test runner. The AndroidJUnit4 test
* runner instantiates a delegate test runner, which is the actual test runner. It is either
* a Robolectric test runner, or something else.
*/
private val Class<*>.usesRobolectricRunner: Boolean
get() = isAndroidJUnit4Runner && getDelegateTestRunner().isRobolectricRunner
private val Class<*>.isRobolectricRunner: Boolean
get() = RobolectricTestRunners.any { it.isAssignableFrom(this) }
private val Class<*>.isAndroidJUnit4Runner: Boolean
get() = AndroidJUnit4::class.java.isAssignableFrom(this)
/**
* Returns the delegate test runner used by the AndroidJUnit4 test runner. This uses the
* exact same method to resolve the class as AndroidJUnit4 does.
*/
private fun getDelegateTestRunner(): Class<*> {
val delegateRunner = System.getProperty("android.junit.runner", null)
?: if (hasRobolectricOnHost()) {
RobolectricTestRunnerClassName
} else {
AndroidJUnit4ClassName
}
// The runner has already been instantiated, so this should succeed
return Class.forName(delegateRunner)
}
/**
* Returns if RobolectricTestRunner is on the classpath, _and_ if we're running on the host.
* This is the same detection method as used in AndroidJUnit4.
*/
private fun hasRobolectricOnHost(): Boolean {
val isAndroidRuntime =
System.getProperty("java.runtime.name")?.lowercase()?.contains("android") ?: false
return !isAndroidRuntime && try {
// Load RobolectricTestRunner. If it succeeds, it's on the classpath
Class.forName(RobolectricTestRunnerClassName); true
} catch (e: ClassNotFoundException) {
// If it fails, it's not on the classpath
false
}
}
}