attest
attest is a small package of type-safe assertion helpers. Under the hood, it uses cmp for equality testing and diffing. You may enjoy attest if you prefer:
- Type safety: it's impossible to compare values with different types.
- Brevity: assertions usually print diffs rather than full values.
- Minimalism: just a few assertions, not a whole DSL.
- Natural ordering: every assertion uses
got == wantorder. - Interoperability: assertions work with any
cmp.Option.
An example
package main
import (
"testing"
"time"
"github.com/akshayjshah/attest"
)
func TestExample(t *testing.T) {
attest.Equal(t, 1, 1)
attest.Approximately(
t,
time.Minute - 1, // got
time.Minute, // want
time.Second, // tolerance
)
attest.Zero(t, "")
attest.Contains(t, []int{0, 1, 2}, 2)
var err error
attest.Ok(t, err)
err = fmt.Errorf("read config: %w", io.EOF)
attest.Error(t, err)
attest.ErrorIs(t, err, io.EOF)
// You can enrich the default failure message.
attest.Equal(t, 1, 2, attest.Sprintf("integer %s", "addition"))
// The next two assertions won't compile.
attest.Equal(t, int64(1), int(1))
attest.Approximately(t, 9, 10, 0.5)
}
Failed assertions usually print a diff. Here's an example using attest.Equal:
--- FAIL: TestEqual (0.00s)
attest_test.go:58: got != want
diff (+got, -want):
attest.Point{
X: 1,
- Y: 4.2,
+ Y: 3.5,
}
Status and support
attest supports the two most recent major releases of Go, with a minimum of Go 1.18. It's currently unstable, but I hope to cut a stable 1.0 soon after the Go 1.19 release.
Legal
Offered under the Apache 2 license.
