[SSHD-764] Override default jUnit tests runner so as not to create a new instance for each executed test method

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.0
• Fix Version/s: 1.7.0
• Labels: junit
• Flags: Important
• Assignee: Lyor Goldstein
• Reporter: Lyor Goldstein
• Created: 21/Aug/17 10:49
• Updated: 21/Aug/17 11:47
• Resolved: 21/Aug/17 11:47

Description

The default tests runner (if not specified) is BlockJUnit4ClassRunner its default behavior is to create a new instance of the test class for each executed test method. This can be changed by deriving an ExtendedBlockJUnit4ClassRunner and overriding its createTest method:

public class ExtendedBlockJUnit4ClassRunner {
    private final AtomicReference<Pair<Class<?>, Object>> testHolder = new AtomicReference<>();

protected Object createTest() throws Exception {
    Pair<Class<?>, Object> lastTest = testHolder.get();
    Class<?> lastTestClass = (lastTest == null) ? null : lastTest.getLeft();
    TestClass curTest = getTestClass():
    Class<?> curTestClass = curTest.getJavaClass():
    if (curTestClass == lastTestClass) {
        return lastTest.getRight();
    }

    Object instance = curTest.getOnlyConstructor().newInstance();
    testHolder.set(Pair.of(curTestClass, instance));
    return instance;
}