@Test
public void testGetScaleFactor_noScalefactorAttribute() {

    final Variable variable = mock(Variable.class);
    when(variable.findAttribute("scale_factor")).thenReturn(null);
    assertEquals(1.0, NcTools.getScaleFactor(variable), 1e-8);
    verify(variable, times(1)).findAttribute("scale_factor");
    verifyNoMoreInteractions(variable);
}