Unit testing: why is the expected argument always first in equality tests?

Question

Why is it that every unit testing framework (that I know of) requires the expected value in equality tests to always be the first argument:

Assert.AreEqual(42         


        

Answer 1

Nobody knows and it is the source of never ending confusions. However not all frameworks follow this pattern (to a greater confusion):

1. FEST-Assert uses normal order:

   assertThat(Util.GetAnswerToLifeTheUniverseAndEverything()).isEqualTo(42);
   

2. Hamcrest:

   assertThat(Util.GetAnswerToLifeTheUniverseAndEverything(), equalTo(42))
   

3. ScalaTest doesn't really make a distinction:

   Util.GetAnswerToLifeTheUniverseAndEverything() should equal (42)