最近在搭建`Jenkins`环境，实现`Android`自动化编译的过程中，由于内网服务器不能访问外网，因此只能配置`Robolectric`访问内网的服务器。
根据官方文档 Configuring Robolectric，发现如果要更改`Robolectric`默认的下载服务器链接地址，需要在项目的每个`lib`库中都配置如下参数，才能实现：
android {
testOptions {
unitTests.all {
systemProperty 'robolectric.dependency.repo.url', 'https://local-mirror/repo'
systemProperty 'robolectric.dependency.repo.id', 'local'
}
}
}
但是这样配置有一个问题，就是没办法动态调整链接地址。
而我们使用
$ bash gradlew clean build -Drobolectric.dependency.repo.url=http://127.0.0.1/jcenter
手工指定的参数，并没有在编译的时候生效。
参数丢失的原因是因为测试用例在新的`JVM`中执行，传入的参数不会自动带给新创建的`JVM`。
这时需要在`Gradle`脚本中将读到的值重新设到系统属性里面，才可以被`Java`程序读到。
android {
testOptions {
unitTests.all {
//命令行下 单元测试可能卡住的问题
jvmArgs '-noverify'
//robolectric外部指定下载资源链接的参数，使用 -D 参数指定 bash gradlew clean build -Drobolectric.dependency.repo.url=http://127.0.0.1/jcenter
systemProperty 'robolectric.dependency.repo.url', System.getProperty("robolectric.dependency.repo.url")
systemProperty 'robolectric.dependency.repo.id', System.getProperty("robolectric.dependency.repo.id")
}
}
}
每个项目的`build.gradle`中都增加上面的配置之后，就可以保证在外部编译的时候动态指定参数了。
在 Android Studio Chipmunk | 2021.2.1 Patch 1 以及以上的版本，可能会发生如下报错：
URI is not absolute java.lang.IllegalArgumentException: URI is not absolute at java.base/java.net.URL.fromURI(URL.java:692) at java.base/java.net.URI.toURL(URI.java:1116) at org.robolectric.internal.dependency.MavenArtifactFetcher.getRemoteUrl(MavenArtifactFetcher.java:138) at org.robolectric.internal.dependency.MavenArtifactFetcher.fetchToStagingRepository(MavenArtifactFetcher.java:145) at org.robolectric.internal.dependency.MavenArtifactFetcher.fetchArtifact(MavenArtifactFetcher.java:65) at org.robolectric.internal.dependency.MavenDependencyResolver.lambda$getLocalArtifactUrls$0(MavenDependencyResolver.java:80) at org.robolectric.internal.dependency.MavenDependencyResolver.whileLocked(MavenDependencyResolver.java:100) at org.robolectric.internal.dependency.MavenDependencyResolver.getLocalArtifactUrls(MavenDependencyResolver.java:75) at org.robolectric.internal.dependency.MavenDependencyResolver.getLocalArtifactUrls(MavenDependencyResolver.java:65) at org.robolectric.internal.dependency.MavenDependencyResolver.getLocalArtifactUrl(MavenDependencyResolver.java:116) at org.robolectric.plugins.LegacyDependencyResolver.getLocalArtifactUrl(LegacyDependencyResolver.java:89) at org.robolectric.plugins.DefaultSdkProvider$DefaultSdk.getJarPath(DefaultSdkProvider.java:146) at org.robolectric.internal.AndroidSandbox$SdkSandboxClassLoader.<init>(AndroidSandbox.java:102) at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) at org.robolectric.util.inject.Injector.inject(Injector.java:250) at org.robolectric.util.inject.Injector.lambda$memoized$1(Injector.java:232) at org.robolectric.util.inject.Injector$MemoizingProvider.get(Injector.java:498) at org.robolectric.util.inject.Injector.getInstanceInternal(Injector.java:224) at org.robolectric.util.inject.Injector.resolveDependencies(Injector.java:296) at org.robolectric.util.inject.Injector.inject(Injector.java:248) at org.robolectric.util.inject.Injector.lambda$memoized$1(Injector.java:232) at org.robolectric.util.inject.Injector$MemoizingProvider.get(Injector.java:498) at org.robolectric.util.inject.Injector.getInstanceInternal(Injector.java:224) at org.robolectric.util.inject.Injector.getInstance(Injector.java:208) at org.robolectric.util.inject.Injector.access$700(Injector.java:96) at org.robolectric.util.inject.Injector$ScopeBuilderProvider.create(Injector.java:564) at org.robolectric.util.inject.Injector$ScopeBuilderProvider.lambda$get$0(Injector.java:547) at com.sun.proxy.$Proxy19.build(Unknown Source) at org.robolectric.internal.SandboxManager.getAndroidSandbox(SandboxManager.java:57) at org.robolectric.RobolectricTestRunner.getSandbox(RobolectricTestRunner.java:285) at org.robolectric.RobolectricTestRunner.getSandbox(RobolectricTestRunner.java:68) at org.robolectric.internal.SandboxTestRunner$2.evaluate(SandboxTestRunner.java:236) at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63) at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329) at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293) at org.robolectric.internal.SandboxTestRunner$1.evaluate(SandboxTestRunner.java:93) at org.junit.runners.ParentRunner.run(ParentRunner.java:413) at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110) at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58) at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38) at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62) at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.base/java.lang.reflect.Method.invoke(Method.java:566) at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36) at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24) at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33) at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94) at com.sun.proxy.$Proxy2.processTestClass(Unknown Source) at org.gradle.api.internal.tasks.testing.worker.TestWorker$2.run(TestWorker.java:176) at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129) at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100) at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60) at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56) at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:133) at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:71) at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69) at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)
该报错的原因是 Android Studio 没有正确读取我们配置的 robolectric.dependency.repo.url 环境变量，导致无法成功下载，当然也可能是由于高版本不支持 HTTP ，链接地址必须是 HTTPS 导致此问题，这个没有深究。
解决方法是，在命令行执行
$ bash gradlew clean build -Drobolectric.dependency.repo.url=http://127.0.0.1/jcenter
确保在当前用户目录下的 .m2 目录下，成功完成 robolectric 需要的全部文件的下载。这样，执行测试用例的时候，就可以从本地获取依赖文件，而不需要再去服务器上获取。