Test Behaviour, Not Implementation

&#xA; &#xA; &#xA; &#xA; &#xA; &#xA;&#xA;&#xA; Test behaviour, not implementation &#xA; Most testing arguments get lost in theoretical minutiae and miss the point: validating correctness.&#xA;Testing units at every level makes tests brittle and code resistant to change. Testing full vertical&#xA;slices is too coarse - it&rsquo;s hard to cover invariants and edge cases. &#xA; What you want is…