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If you write an DistributedTest to expose a bug and confirm its fix, then you should name it with the suffix *RegressionTest. Otherwise you should use the suffix *DistributedTest or *DUnitTest.

Preferred Testing Frameworks and Libraries for Geode DistributedTests

Overall Framework

• JUnit 4 (including Rules)
• Paramerized – JUnit 4.12 has a bug which prevents Parameterized and Category from working together properly
  • Please use CategoryWithParameterizedRunnerFactory from Geode when using Parameterized (see GEODE-1350)
• TemporaryFolder – provides isolated file system that will be cleaned up after the test
• TestName – provides name of the test method currently being tested
• ErrorCollector – use this when performing assertions in callbacks such as CacheListener

Assertion Library

• AssertJ – richer API with better failure messages than JUnit 4 Assert

Mocking Library

• Mockito
• PowerMock – use this as a last resort – refactoring code to facilitate better testing is preferred

Expected Exceptions

• Use AssertJ or Catch-Exception instead of JUnit 4 Rule ExpectedException
• AssertJ (assertThatThrownBy) – this is the cleanest and preferred way to test for expected exception
• Catch-Exception – better support for complex nesting of exceptions or exceptions with unusual APIs

Additional 3rd Party Libraries for UnitTests

• JUnitParams – provides test method parameterization (usually better to use than JUnit 4 Parameterized)
• System Rules – powerful set of JUnit 4 Rules
  • RestoreSystemProperties
• Awaitility – useful for awaiting asynchronous conditions

Custom Geode JUnit 4 Rules

• ExecutorServiceRule – provides ExecutorService for concurrent testing
• ExpectedTimeoutRule – verifies that an API times out and potentially throws TimeoutException
• JarFileRule – creates a Jar file in an internal TemporaryFolder containing a dynamically generated class
• RequiresGeodeHome – asserts precondition that GEODE_HOME system property is specified
• RestoreLocaleRule – restores JVM to original Locale
• RestoreTCCLRule – restores Thread Context Class Loader
• RetryRule – retries a test until it passes or exceeds specified number of retries
• TemporaryFileRule – destroys specified files or directories that aren't created in a TemporaryFolder
• UseJacksonForJsonPathRule – specifies that JsonPath should use Jackson instead of its default JSON library
• GfshRule – allows use of Gfsh script string to fork a JVM process in an IntegrationTest

Custom Geode JUnit 4 Rules For DUnit

• DistributedTestRule – launches the DUnit VMs
• CacheRule – simple Cache creation and reference for all DUnit VMs
• ClusterStartupRule – creates Server or Locator in any DUnit VM
• DistributedDisconnectRule – disconnects all DUnit VMs
• DistributedRestoreSystemProperties – extends RestoreSystemProperties for all DUnit VMs
• DistributedUseJacksonForJsonPathRule – extends UseJacksonForJsonPathRule for all DUnit VMs
• SerializableTestName – extends TestName to be serializable
• SharedCountersRule – shared counter API for all DUnit VMs
• SharedErrorCollector – extends ErrorCollector for all DUnit VMs

Custom Geode DUnit API Classes

• AsyncInvocation – return type from VM#invokeAsync and implements Future
• Disconnect – disconnect in all or specified VM
• Host – provides the DUnit VMs
• VM – provides invocation API for a DUnit VM

Custom Geode DUnit TestCases

• DistributedTestCase – extend this class for an old-school DUnit test
• CacheTestCase – adds Cache API to DistributedTestCase

Examples of actual tests

Examples of some good DistributedTests:

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