fix test

Author: samanhappy

monkey.go

@@ -64,7 +64,7 @@ func PatchInstanceMethod(target reflect.Type, methodName string, replacement int
 		panic(fmt.Sprintf("unknown method %s", methodName))
 	}
 
-	o := &opt{}
+	o := &opt{global: true}
 	r := reflect.ValueOf(replacement)
 	patchValue(m.Func, r, o)
 	return &PatchGuard{m.Func, r, o}

monkey_test.go

@@ -90,9 +90,9 @@ func (f *f) No() bool { return false }
 func TestOnInstanceMethod(t *testing.T) {
 	i := &f{}
 	assert(t, !i.No())
-	monkey.PatchInstanceMethod(reflect.TypeOf(i), "No", func(_ *f) bool { return true })
+	pg := monkey.PatchInstanceMethod(reflect.TypeOf(i), "No", func(_ *f) bool { return true })
 	assert(t, i.No())
-	assert(t, monkey.UnpatchInstanceMethod(reflect.TypeOf(i), "No"))
+	pg.Unpatch()
 	assert(t, !i.No())
 }