testing

func AssertLaws ¶

func AssertLaws[E, A, B, C any](t *testing.T,
	eqe EQ.Eq[E],
	eqa EQ.Eq[A],
	eqb EQ.Eq[B],
	eqc EQ.Eq[C],

	ab func(A) B,
	bc func(B) C,
) func(a A) bool

AssertLaws asserts that the Either monad satisfies the monad laws. This includes testing:

• Identity laws (left and right identity)
• Associativity law
• Functor laws
• Applicative laws

Parameters:

• t: Testing context
• eqe, eqa, eqb, eqc: Equality predicates for the types
• ab: Function from A to B for testing
• bc: Function from B to C for testing

Returns a function that takes a value of type A and returns true if all laws hold.

Example:

func TestEitherLaws(t *testing.T) {
    eqInt := eq.FromStrictEquals[int]()
    eqString := eq.FromStrictEquals[string]()
    eqError := eq.FromStrictEquals[error]()

    ab := strconv.Itoa
    bc := func(s string) bool { return len(s) > 0 }

    testing.AssertLaws(t, eqError, eqInt, eqString, eq.FromStrictEquals[bool](), ab, bc)(42)
}