@Test
public void testDiff() {

    IElectronContainer ec1 = mock(IElectronContainer.class);
    IElectronContainer ec2 = mock(IElectronContainer.class);
    when(ec1.getElectronCount()).thenReturn(2);
    when(ec2.getElectronCount()).thenReturn(3);
    String result = ElectronContainerDiff.diff(ec1, ec2);
    Assert.assertNotNull(result);
    Assert.assertNotSame(0, result.length());
    assertContains(result, "ElectronContainerDiff");
    assertContains(result, "eCount");
    assertContains(result, "2/3");
}