func Ok(tb testing.TB, err error) {
	tb.Helper()
	if err != nil {
		_, file, line, _ := runtime.Caller(1)
		tb.Fatalf("%s:%d: unexpected error: %s\n", filepath.Base(file), line, err.Error())
	}
}
Ok fails the test if an err is not nil.
package test
import (
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"runtime"
	"sort"
	"testing"
	"github.com/google/go-cmp/cmp"
)
func Assert(tb testing.TB, condition bool, msg string, v ...interface{}) {
	tb.Helper()
	if !condition {
		_, file, line, _ := runtime.Caller(1)
		tb.Fatalf("%s:%d: "+msg+"\n", append([]interface{}{filepath.Base(file), line}, v...)...)
	}
}