JUnit

External

• https://www.infoq.com/presentations/junit-5-demo
• Latest JUnit 4 version: https://junit.org/junit4/
• https://junit.org/junit4/javadoc/latest/

Internal

• Mockito

Dependencies

dependencies {
    testImplementation "junit:junit:4.12"
}

JUnit and Gradle

The only configuration required to enable unit testing in a Gradle project is to apply the Java plugin and declared JUnit as testImplementation:

apply plugin: 'java'

repositories {
    mavenCentral()
}

dependencies {
    ...
    testImplementation "junit:junit:4.12"
}

This will allow to declare @Test methods and will enable result parsing to generate HTML reports.

Passing System Properties to Tests

See:

Gradle Java Plugin - Passing System Properties to Tests

Concepts

Test Runner

A JUnit plugin that provides custom testing behavior. Specified with @RunWith.

Annotations

• @RunWith
• @BeforeClass/@AfterClass
• @Before/@After
• @Ignore

Patterns

• JUnit Exception Testing

JUnit XML Reporting File Format

https://llg.cubic.org/docs/junit/

This file format is understood by the Jenkins junit step, which generates Jenkins test reports from it.

<?xml version="1.0" encoding="UTF-8"?>
<!-- If only a single testsuite element is present, the testsuites element can be omitted. 
     All attributes are optional.
-->
<testsuites disabled="" <!-- total number of disabled tests from all testsuites. -->
            errors=""   <!-- total number of tests with error result from all testsuites. -->
            failures="" <!-- total number of failed tests from all testsuites. -->
            name=""
            tests=""    <!-- total number of tests from all testsuites. Some software may expect to only see the number of successful tests from all testsuites though. -->
            time=""     <!-- time in seconds to execute all test suites. -->
	    >

  <!-- testsuite can appear multiple times, if contained in a testsuites element.
       It can also be the root element. -->
  <testsuite name=""      <!-- Full (class) name of the test for non-aggregated testsuite documents.
                               Class name without the package for aggregated testsuites documents. Required -->
	     tests=""     <!-- The total number of tests in the suite, required. -->
	     disabled=""  <!-- the total number of disabled tests in the suite. optional. not supported by maven surefire. -->
             errors=""    <!-- The total number of tests in the suite that errored. An errored test is one that had an unanticipated problem,
                               for example an unchecked throwable; or a problem with the implementation of the test. optional -->
             failures=""  <!-- The total number of tests in the suite that failed. A failure is a test which the code has explicitly failed
                               by using the mechanisms for that purpose. e.g., via an assertEquals. optional -->
             hostname=""  <!-- Host on which the tests were executed. 'localhost' should be used if the hostname cannot be determined. optional. not supported by maven surefire. -->
	     id=""        <!-- Starts at 0 for the first testsuite and is incremented by 1 for each following testsuite. optional. not supported by maven surefire. -->
	     package=""   <!-- Derived from testsuite/@name in the non-aggregated documents. optional. not supported by maven surefire. -->
	     skipped=""   <!-- The total number of skipped tests. optional -->
	     time=""      <!-- Time taken (in seconds) to execute the tests in the suite. optional -->
	     timestamp="" <!-- when the test was executed in ISO 8601 format (2014-01-21T16:17:18). Timezone may not be specified. optional. not supported by maven surefire. -->
	     >

    <!-- Properties (e.g., environment settings) set during test execution.
         The properties element can appear 0 or once. -->
    <properties>
      <!-- property can appear multiple times. The name and value attributres are required. -->
      <property name="" value=""/>
    </properties>

    <!-- testcase can appear multiple times, see /testsuites/testsuite@tests -->
    <testcase name=""       <!-- Name of the test method, required. -->
	      assertions="" <!-- number of assertions in the test case. optional. not supported by maven surefire. -->
	      classname=""  <!-- Full class name for the class the test method is in. required -->
	      status=""     <!-- optional. not supported by maven surefire. -->
	      time=""       <!-- Time taken (in seconds) to execute the test. optional -->
	      >

      <!-- If the test was not executed or failed, you can specify one of the skipped, error or failure elements. -->

      <!-- skipped can appear 0 or once. optional -->
      <skipped message=""   <!-- message/description string why the test case was skipped. optional -->
	  />

      <!-- error indicates that the test errored.
           An errored test had an unanticipated problem.
           For example an unchecked throwable (exception), crash or a problem with the implementation of the test.
           Contains as a text node relevant data for the error, for example a stack trace. optional -->
      <error message="" <!-- The error message. e.g., if a java exception is thrown, the return value of getMessage() -->
	     type=""    <!-- The type of error that occured. e.g., if a java execption is thrown the full class name of the exception. -->
	     >error description</error>

      <!-- failure indicates that the test failed.
           A failure is a condition which the code has explicitly failed by using the mechanisms for that purpose.
           For example via an assertEquals.
           Contains as a text node relevant data for the failure, e.g., a stack trace. optional -->
      <failure message="" <!-- The message specified in the assert. -->
	       type=""    <!-- The type of the assert. -->
	       >failure description</failure>

      <!-- Data that was written to standard out while the test was executed. optional -->
      <system-out>STDOUT text</system-out>

      <!-- Data that was written to standard error while the test was executed. optional -->
      <system-err>STDERR text</system-err>
    </testcase>

    <!-- Data that was written to standard out while the test suite was executed. optional -->
    <system-out>STDOUT text</system-out>
    <!-- Data that was written to standard error while the test suite was executed. optional -->
    <system-err>STDERR text</system-err>
  </testsuite>
</testsuites>

More details:

Jenkins junit step