testing

func AssertLaws ¶

func AssertLaws[A, B, C any](t *testing.T,
	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 the monad laws for the Option monad. This function verifies that Option satisfies the functor, applicative, and monad laws.

The laws tested include:

• Functor laws: identity and composition
• Applicative laws: identity, composition, homomorphism, and interchange
• Monad laws: left identity, right identity, and associativity

Parameters:

• t: testing instance
• eqa, eqb, eqc: equality predicates for types A, B, and C
• ab: a function from A to B for testing
• bc: a 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 TestOptionLaws(t *testing.T) {
    eqInt := eq.FromStrictEquals[int]()
    eqString := eq.FromStrictEquals[string]()
    eqBool := eq.FromStrictEquals[bool]()

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

    assert := AssertLaws(t, eqInt, eqString, eqBool, ab, bc)
    assert(42) // verifies laws hold for value 42
}