Composable assertions
This module contains functions for building and combining Matchers that
can be used to build up assertions for testing.
import M "mo:matchers/Matchers";
import T "mo:matchers/Testable";
assertThat(5 + 5, M.equals(T.nat(10)));
assertThat(5 + 5, M.allOf<Nat>([M.greaterThan(8), M.lessThan(12)]));
assertThat([1, 2], M.array([M.equals(T.nat(1)), M.equals(T.nat(2))]));A Matcher is a composable way of building up assertions for tests
public func assertThat<A>(item : A, matcher : Matcher<A>)Matches an item against a matcher and traps with an error if the
matcher fails. This is primarily for experimentation and one-offs. For
writing an actual test suite you probably want to use the functions in
Suite.
public func attempt<A>(item : A, matcher : Matcher<A>) : {#success; #fail : Text}Matches an item against a matcher and returns null in case the
match succeeds and ?errorMessage if it fails.
public func contramap<A, B>(matcher : Matcher<A>, f : B -> A) : Matcher<B>Turns a Matcher for As into a Matcher for Bs by using f as an adapter.
public func appendText(text : Text)public func toText() : TextMatchers describe match failures by inserting them into a Description.
public func anything<A>() : Matcher<A>Always matches, useful if you don’t care what the object under test is
public func describedAs<A>(msg : Text, matcher : Matcher<A>) : Matcher<A>Decorator that allows adding a custom failure description
public func equals<A>(expected : T.TestableItem<A>) : Matcher<A>Matches values equal to an expected Testable
public func greaterThan<A <: Int>(expected : Int) : Matcher<A>Matches values greater than expected
public func greaterThanOrEqual<A <: Int>(expected : Int) : Matcher<A>Matches values greater than or equal to expected
public func lessThan<A <: Int>(expected : Int) : Matcher<A>Matches values less than expected
public func lessThanOrEqual<A <: Int>(expected : Int) : Matcher<A>Matches values less than or equal to expected
public func inRange<A <: Int>(lower : Int, upper : Int) : Matcher<A>Matches values for being in inclusive range [lower .. upper]
public func allOf<A>(matchers : [Matcher<A>]) : Matcher<A>Matches if all matchers match, short circuits (like and)
public func anyOf<A>(matchers : [Matcher<A>]) : Matcher<A>Matches if any matchers match, short circuits (like or)
public func not_<A>(matcher : Matcher<A>) : Matcher<A>Matches if the wrapped matcher doesn’t match and vice versa
public func array<A>(matchers : [Matcher<A>]) : Matcher<[A]>Test an array’s elements against an array of matchers
public func isSome<A>() : Matcher<?A>Tests that a value is not-null
public func isNull<A>() : Matcher<T.TestableItem<?A>>Tests that a value is null