Java™ Application Development on Linux - Dator

13.5 Writing Test Cases307• assertTrue( boolean expression )• assertFalse( boolean expression )• assertNull (Object)• assertNotNull (Object)• assertSame (Object1, Object2)• assertNotSame (Object1, Object2)• fail()Each of the assert methods comes in two “flavors,” one with a messageString and one without. For example, there is a method assertTrue() whichtakes a boolean as its parameter; typically it would be used with an expression,for example: 1assertTrue( (sample actual) );If the condition is not true, an AssertionFailedError is thrown. Thatmeans, among other things, that if/when your test fails, it will stop executingat that point. The tearDown() method, though, will still be executed beforeproceeding to the next test.There is also a method of the same name, assertTrue(), but with aslightly different signature—it adds a String as its first parameter. The stringis the message to be included in the error report. Using this variation onassertTrue(), our example would become:assertTrue("Sample too small", (sample actual));In the same way, assertFalse() has two versions—assertFalse(boolean) and assertFalse(String, boolean)—and soon for all other assert methods.1. Yes, the extra parentheses are not needed; they just make the point that this is a boolean expressionbeing passed as the argument to assertTrue(). We could also have written it as:boolean result = (sample actual);assertTrue(result);Again, the extra parentheses are used just to make it clearer.