question: public static void assertEqualsNaN ( String message , double expected , double actual ) { if ( Double . isNaN ( expected ) ) { if ( ! Double . isNaN ( actual ) ) { throw new AssertionFailedError ( message + " expected: <" + expected + "> but was: <" + actual + ">" ) ; } } else { assertEquals ( message , expected , actual , DELTA ) ; } }
target:  Extends the Junit assertEquals method by additionally checking the doubles for NaN.