Fixed flaky tests caused by SharedMetricRegistries in SharedMetricRegistriesTest.java

[KellyShao]

Fixed flaky test that caused by io.dropwizard.metrics.SharedMetricRegistries in class SharedMetricRegistriesTest.java.

• Issue 1

  • If only run errorsWhenDefaultAlreadySet() method before hasASetOfNames()method, the hasASetOfNames() will failed at

    light-4j/metrics/src/test/java/io/dropwizard/metrics/SharedMetricRegistriesTest.java

    Line 45 in fcded16

    assertThat(SharedMetricRegistries.names())

  • error msg:

      java.lang.AssertionError: 
      Expecting:
        <["one", "borg", "foobah"]>
      to contain only:
        <["one"]>
      but the following elements were unexpected:
        <["borg", "foobah"]>
  

• Issue 2

  • If only run errorsWhenDefaultAlreadySet() method before removesRegistries()method, the removesRegistries() will failed at

    light-4j/metrics/src/test/java/io/dropwizard/metrics/SharedMetricRegistriesTest.java

    Line 54 in fcded16

    assertThat(SharedMetricRegistries.names())

  • error msg:

     java.lang.AssertionError: 
     Expecting:
       <["one", "foobah"]>
     to contain only:
       <["one"]>
     but the following elements were unexpected:
       <["foobah"]>
  

• root cause

  • The SharedMetricRegistries variable is not cleared after each tests.

• solution:
  Added setUp() and tearDown() methods right before and after each tests to clear SharedMetricRegistries.

The flaky tests are found by running iDFlakies, after fixing the issue, there's no flaky tests in SharedMetricRegistriesTest.java

[stevehu]

@KellyShao This is a fantastic tool to detect problematic tests. Thanks a lot for your help.

[stevehu]

Fixed flaky tests caused by SharedMetricRegistries in SharedMetricRegistriesTest.java light-4j master

[stevehu]

Fixed flaky tests caused by SharedMetricRegistries in SharedMetricRegistriesTest.java light-4j master