Go语言不会在不同包的测试文件之间共享代码,因此测试接口定义不会自动重用。我们如何在实践中解决这个问题呢?
使用testing/quick
的示例:
foo/foo.go
:
package foo
type Thing int
const (
X Thing = iota
Y
Z
)
bar/bar.go
:
package bar
import (
"foo"
)
type Box struct {
Thing foo.Thing
}
我们希望对
foo
进行属性测试,因此我们在 Thing
上定义了 testing/quick.Generate
:
foo_test.go
:package foo
import (
"math/rand"
"reflect"
"testing"
"testing/quick"
"time"
)
func (_ Thing) Generate(r *rand.Rand, sz int) reflect.Value {
return reflect.ValueOf(Thing(r.Intn(3)))
}
func TestGenThing(t *testing.T) {
r := rand.New(rand.NewSource(time.Now().UTC().UnixNano()))
for i := 0; i < 5; i++ {
val, _ := quick.Value(reflect.TypeOf(Thing(0)), r)
tng, _ := val.Interface().(Thing)
t.Logf("%#v\n", tng)
}
}
quick.Value
返回期望的范围为 [0,3) 的Thing
们:
$ go test -v foo
=== RUN TestGenThing
--- PASS: TestGenThing (0.00s)
foo_test.go:20: 0
foo_test.go:20: 1
foo_test.go:20: 2
foo_test.go:20: 1
foo_test.go:20: 2
PASS
ok foo 0.026s
我们也要对bar
进行属性测试:
package bar
import (
"math/rand"
"reflect"
"testing"
"testing/quick"
"time"
"foo"
)
func (_ Box) Generate(r *rand.Rand, sz int) reflect.Value {
val, _ := quick.Value(reflect.TypeOf(foo.Thing(0)), r)
tng, _ := val.Interface().(foo.Thing)
return reflect.ValueOf(Box{tng})
}
func TestGenBox(t *testing.T) {
r := rand.New(rand.NewSource(time.Now().UTC().UnixNano()))
for i := 0; i < 5; i++ {
val, _ := quick.Value(reflect.TypeOf(Box{}), r)
box, _ := val.Interface().(Box)
t.Logf("%#v\n", box)
}
}
但是,
Box.Generate
有问题。 foo_test.go
对于bar_test.go
不可用,因此quick.Value()
不会使用Thing.Generate()
:$ GOPATH=$PWD go test -v bar
=== RUN TestGenBox
--- PASS: TestGenBox (0.00s)
bar_test.go:24: bar.Box{Thing:3919143124849004253}
bar_test.go:24: bar.Box{Thing:-3486832378211479055}
bar_test.go:24: bar.Box{Thing:-3056230723958856466}
bar_test.go:24: bar.Box{Thing:-847200811847403542}
bar_test.go:24: bar.Box{Thing:-2593052978030148925}
PASS
ok bar 0.095s
这个问题有解决方法吗?在实践中,人们如何使用testing/quick
(或任何其他带接口的测试库)?