test

An easy-to-use testing module with pleasing syntax and support for custom assertions.

Usage Example

func TestTheFabricOfTheUniverse(t *testing.T) {
	test.That(t, 2 + 2, is.EqualTo(4))
}

Assertions

The core function in this module, That, accepts an Assertion as its last argument. Assertion is simply an interface, so can be implemented to provide custom assertions for specific use cases.

The does, has and is packages contained in this module provide a number of useful assertions. Some of the more commonly used assertions are:

• is.EqualTo
• is.Nil
• is.True
• is.False
• has.Length
• does.Panic

You can also create assertions that use other assertions internally. For example, the does.PanicWithValueThat assertion:

f := func () { panic("ahh!") }
test.That(t, f, does.PanicWithValueThat(is.EqualTo("ahh!")))

or the has.ValueThat assertion:

m := map[string]int{"a": 42}
test.That(t, m, has.ValueThat(is.EqualTo(42)))

Nil and Interfaces

A well known "gotcha" in the Go language is the comparison behavior when comparing nil with an interface that has a type but no value.

For example:

fmt.Printf("%v", io.Writer((*os.File)(nil)) == nil) // false

Which is somewhat unintuitive. This package respects that behavior for all comparison-based assertions except for is.Nil and is.NotNil which consider an interface, map, slice, func or chan with a type, but a nil value, to still be nil.

For example, this test will pass:

test.That(t, io.Writer((*os.File)(nil)), is.Nil)

but this test will fail:

test.That(t, io.Writer((*os.File)(nil)), is.EqualTo(nil))

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