### Question:
Debug implements ActionListener { public void actionPerformed (ActionEvent ev) { System.out.println ("Action command: "+ev.getActionCommand ()); System.out.println (ev.toString ()); System.out.println (""); } Debug(); void actionPerformed(ActionEvent ev);  }### Answer:
@Test public void testActionPerformed() throws Throwable { Debug debug = new Debug(); debug.actionPerformed(new ActionEvent(debug, 100, "testDebugParam3", 100L, 1000)); assertTrue(true, "Test completed without Exception"); }
@Test public void testActionPerformedThrowsNullPointerException() throws Throwable { try { new Debug().actionPerformed(null); fail("Expected NullPointerException to be thrown"); } catch (NullPointerException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertNull(ex.getMessage(), "ex.getMessage()"); } else { assertEquals("Cannot invoke \"java.awt.event.ActionEvent.getActionCommand()\" because \"ev\" is null", ex.getMessage(), "ex.getMessage()"); } } }