testx

Overview ¶

Package testx provides a comprehensive set of generic matchers and assertion utilities for Go testing.

It is designed to be highly extensible, type-safe, and easy to use alongside the standard `testing` package.

Core Assertions ¶

The package provides two primary assertion functions:

• `Expect`: Asserts that an actual value satisfies one or more matchers.
• `ExpectPanic`: Asserts that a function panics, and optionally verifies the panic value against matchers.

Example:

func TestMath(t *testing.T) {
	result := 1 + 1
	testx.Expect(t, result, testx.Equal(2), testx.BeGt(0))

	testx.ExpectPanic(t, func() {
		panic("something went wrong")
	}, testx.Equal("something went wrong"))
}

Matchers ¶

Matchers are the building blocks of assertions. A `Matcher[T]` evaluates an actual value of type `T` and returns whether it meets the expected criteria. The package includes a wide variety of built-in matchers:

• Equality & Comparison: `Equal`, `Be`, `BeGt`, `BeLt`, `IsZero`, etc.
• Collections: `HaveLen`, `HaveCap`, `HaveKey`, `Contains`, `EquivalentSlice`, etc.
• Strings: `HavePrefix`, `HaveSuffix`, `ContainsSubString`, `MatchRegexp`.
• Types & Interfaces: `BeAssignableTo`, `BeConvertibleTo`, `IsType`.
• Errors: `IsError`, `AsError`, `ErrorEqual`, `Succeed`, `Failed`, etc.

Custom Matchers ¶

You can easily create custom matchers using `NewMatcher` or `NewComparedMatcher`:

func BeEven() testx.Matcher[int] {
	return testx.NewMatcher("BeEven", func(actual int) bool {
		return actual%2 == 0
	})
}

BDD Integration ¶

For a more expressive, Behavior-Driven Development style, consider using the `github.com/xoctopus/x/testx/bdd` sub-package, which builds upon the matchers defined here.