### Question:
NullSCM extends SCM { @Override public int hashCode() { return 56; }  SCMRevisionState calcRevisionsFromBuild(AbstractBuild<?, ?> build, Launcher launcher, TaskListener listener); boolean checkout(AbstractBuild<?,?> build, Launcher launcher, FilePath remoteDir, BuildListener listener, File changeLogFile); ChangeLogParser createChangeLogParser(); @Override boolean equals(Object o); @Override int hashCode();  }### Answer:
@Test public void testHashCode() { assertEquals(expectedResult, scm1.hashCode() == (scm2 == null? 0: scm2).hashCode()); }