### Question:
ActionKeys { public void setActionClassName(String value) { if (value == null) { throw new IllegalArgumentException("ActionClassName == null"); } _actionClassName = value; } ActionKeys();  ActionKeys(String actionClassName, String accelerator, int mnemonic); String getActionClassName(); int getMnemonic(); String getAccelerator(); void setActionClassName(String value); void setAccelerator(String value); void setMnemonic(int value);  }### Answer:
@Test (expected = IllegalArgumentException.class) public void testNullActionClassName() { classUnderTest.setActionClassName(null); }