Fix more non-idempotent unit tests

[kaiyaok2]

Fixes #14171.

The Problem

Followup of #14135 - fixing more non-idempotent unit tests (tests that pass in the first run but fails in repeated runs in the same environment in isolation)

All Non-Idempotent Tests & Proposed Fix

ClassGeneratorTest#test and ClassGeneratorTest#testMain0

Reason: Similar as described in #14135, these tests employs the ClassGenerator to configure a custom class with hard-coded names, and then invokes ClassGenerator.toClass() to instantiate the desired Class<?> object. However, within ClassGenerator.toClass(), the invoked method javassist.ClassPool.makeClass() is called to create the class. Given that Javassist freezes a class upon its initial loading (ensuring classes cannot be altered or removed at runtime), repeated invocations of the two unit tests fail as the class names remain unchanged, leading to class generation errors.

Error message of one of the tests in the repeated run:

java.lang.RuntimeException: org.apache.dubbo.common.bytecode.Bean$Builder: frozen class (cannot edit)

Fix: Assign a unique ID to each class to be generated in the same classloader.

ChannelHandlerDispatcherTest#test

Reason: The MockChannelHandler class has stores metrics like sentCount and connectedCount as static variables. However, there're no reset methods to clear these metrics after a round of test execution. Therefore, in the repeated runs, metrics like sentCount will be an accumulative count across multiple test runs. This will make the assertions fail.

Error message in the repeated run:

org.opentest4j.AssertionFailedError: expected: <4> but was: <2>

Fix: Add a reset() methods to clear all metrics, and call this reset() method after each test execution.

RpcStatusTest#testStatistics, RpcStatusTest#testBeginCountEndCount and RpcStatusTest#testBeginCountEndCountInMultiThread

Reason: For each test method, RpcStatus records metrics retrieved by methods like getTotal(). However, the metrics are not reset before the repeated runs of the same test method, so the values returned by methods like getTotal() would be an accumulative count of multiple test runs, causing the assertions fail.

Error message of one of the tests in the repeated run:

org.opentest4j.AssertionFailedError: expected: <8> but was: <4>

Fix: Call RpcStatus.removeStatus() to reset the metrics corresponding to the url and the method name for each test at the start of test execution.

DubboMonitorTest#testMonitorFactory

Reason: monitorFactory.getMonitor() uses the hard-coded port number 17979. However, the port will be occupied by the first test execution, so repeated run will fail to start the server since the address has already been used.

Error message:

org.apache.dubbo.rpc.RpcException: Fail to start server(url: dubbo://127.0.0.1:17979/org.apache.dubbo.monitor.MonitorService?channel.readonly.sent=true&codec=dubbo&heartbeat=60000) Failed to bind NettyServer on /0.0.0.0:17979, cause: Address already in use

Fix: Find a free port using java.net.ServerSocket and use it.

PrometheusMetricsThreadPoolTest#testExporterThreadpoolName and PrometheusMetricsReporterTest#testExporter

Reason: The tests attempt to create a prometheusExporterHttpServer in each execution. However, in the first execution, the server is created but not shut down after execution. Therefore, repeated test executions will throw a runtime exception since the address corresponding to the server is already in use.

Error Message:

java.lang.RuntimeException: java.net.BindException: Address already in use

Fix: Extract prometheusExporterHttpServer as a field and stop it in the tearDown() method to ensure each test execution starts with a fresh state.

Register Center Integration Tests

• MultipleRegistryCenterInjvmIntegrationTest#integrate
• SingleRegistryCenterInjvmIntegrationTest#integrate
• MultipleRegistryCenterExportMetadataIntegrationTest#integrate
• SingleRegistryCenterExportMetadataIntegrationTest#integrate
• MultipleRegistryCenterServiceDiscoveryRegistryIntegrationTest#integrate
• MultipleRegistryCenterExportProviderIntegrationTest#integrate
• SingleRegistryCenterExportProviderIntegrationTest#integrate
  Reason: These integration tests set the static string PROVIDER_APPLICATION_NAME to null in its tearDown() method. This causes repeated runs to fail to find the corresponding configuration. There's really no need to clear PROVIDER_APPLICATION_NAME in the reset method since each integration test class has its globally unique provide application name and they're not interdependent on each other.

Error Message:

java.lang.IllegalStateException: No application config found or it's not a valid config! Please add <dubbo:application name="..." /> to your spring config.

Fix: Do not set PROVIDER_APPLICATION_NAME to null when tearing down.

ReferenceCacheTest#testGetCacheDiffReference

Reason: Though the XxxMockReferenceConfig instance configCopy is re-constructed in each test execution, the configCopy.getCounter() will return accumulative counts across different runs since counter is static (of global scope). Therefore, the assertion assertEquals(0L, configCopy.getCounter()); will fail in repeated runs.

Error Message:

org.opentest4j.AssertionFailedError: expected: <0> but was: <1>

Fix: Call XxxMockReferenceConfig.setCounter(0) in the setUp() method.

LiveTest#testExecute

Reason: The test sets the check return value of MockLivenessProbe to true during the test execution, but does not reset it back to false when the test finishes. Therefore, Assertions.assertEquals(result, "false"); will fail in the repeated run.

Error Message:

org.opentest4j.AssertionFailedError: expected: <true> but was: <false>

Fix: Ensure the return value of MockLivenessProbe is set to the default value (false) in the tearDown() method.

Verifying this change

After the patch, running the tests repeatedly in the same environment will not lead to failures.

Checklist

• Make sure there is a GitHub_issue field for the change (usually before you start working on it). Trivial changes like typos do not require a GitHub issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
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• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
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[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[CrazyHZM]

Thank you for it.