java - 当前测试使用 MapState 的 DoFn 的最佳实践是什么

Question

我正在编写一段使用 org.apache.beam.sdk.state.MapState 的数据流转换实现缓存功能。然而在介绍MapState ，单元测试开始功能障碍。异常显示:java.lang.UnsupportedOperationException: Parameter StateParameter{referent=StateDeclaration{id=cache, field=private final org.apache.beam.sdk.state.StateSpec xxxxFn.cache, stateType=org.apache.beam.sdk.state.MapState<java.lang.String, object>}} not supported by DoFnTester

所以如果DoFnTester不再是一个选项，当前测试使用 MapState 的 DoFn 的最佳实践是什么？

附言我目前使用的是 Beam 2.0.0，我无法升级到 2.2.0，因为 https://issues.apache.org/jira/browse/BEAM-3693

这是完整的跟踪:

java.lang.UnsupportedOperationException: Parameter StateParameter{referent=StateDeclaration{id=cache, field=private final org.apache.beam.sdk.state.StateSpec xxxxFn.cache, stateType=org.apache.beam.sdk.state.MapState<java.lang.String, object>}} not supported by DoFnTester
    at org.apache.beam.sdk.transforms.DoFnTester$5.dispatchDefault(DoFnTester.java:725)
    at org.apache.beam.sdk.transforms.DoFnTester$5.dispatchDefault(DoFnTester.java:710)
    at org.apache.beam.sdk.transforms.reflect.DoFnSignature$Parameter$Cases$WithDefault.dispatch(DoFnSignature.java:255)
    at org.apache.beam.sdk.transforms.reflect.DoFnSignature$Parameter.match(DoFnSignature.java:193)
    at org.apache.beam.sdk.transforms.DoFnTester.<init>(DoFnTester.java:709)
    at org.apache.beam.sdk.transforms.DoFnTester.of(DoFnTester.java:92)
    at xxxxFnTest.testNormalRun(GetPredictionsFnTest.java:50)
    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:564)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)

Answer 1

Java DirectRunner 是测试您的 DoFn 的最佳方式，无论它使用什么功能。

使用 DoFnTester 可以让您通过测试不可行的场景而错过可能真正发生的场景来获得错误的信心。由于这个原因，以及错误/缺乏维护，DoFnTester 现已弃用，您应该尝试摆脱它。

要控制水印、处理时钟和元素捆绑，您可以使用 TestStream，如 Beam blog 中所述。 .