The other day I was thinking about Rich Hickey’s keynote at last year’s Conj. He goes into how the literal maps (or hashes or hashmaps or however a language prefers to call them) are really functions too. A function in maths is a mapping between sets and that’s what maps are.
Then that makes functions we normally write are just like that too, except the mappings are more abstract and defined through code. Because the mappings are so complex and indirect, we write tests to check (automated) that the mapping we defined through code is correct.
Obviously defining the exact mappings for every possible combination of the input set(s) is not feasible (that’d be a map, the end). But if “all” is not possible then how much is? What exactly is the absolute minimum amount of test( case)s that’s useful?
