Represents a function from a subject to a verdict.

The result of applying a claim to a subject.

A claim about a subject will either be accepted or rejected.

Claim that the subject is equal to the provided value.

The first argument to this function converts a value of some type to a string, which is used to produce readable messages if the claim is rejected. Instead of providing this string-generating function each time, I suggest adding a helper function that just uses the Debug.toString function like so:

equals : a -> Claim a
equals =
  Spec.Claim.isEqual Debug.toString

Then just use your equals function whenever you need to claim that a subject is equal to some value.

Claim that the subject is True

Claim that the subject is False

Claim that the subject is a list where the following claims are satisfied:

• the subject has the same length as the provided list
• for each item in the subject, that item satisfies the corresponding claim in the provided list.

For example:

[ 1, 2, 3 ]
  |> Spec.Claim.isListWhere
      [ Spec.Claim.isEqualTo Debug.toString 1
      , Spec.Claim.isEqualTo Debug.toString 27
      , Spec.Claim.isEqualTo Debug.toString 3
      ]

would result in a rejected claim, since 2 is not equal to 27.

Claim that the subject is a list such that:

• there is an item at the given index
• that item satisfies the given claim

Claim that the subject is a list with the given length.

Claim that the subject is the Just case of the Maybe type.

Claim that the subject is the Nothing case of the Maybe type.

Combine multiple claims into one.

If any of the claims is rejected, then the combined claim is rejected.