Catch

func Catch(target, expectedValue any) TestDeep

Catch is a smuggler operator. It allows to copy data in target on the fly before comparing it as usual against expectedValue.

target must be a non-nil pointer and data should be assignable to its pointed type. If BeLax config flag is true or called under Lax (and so JSON) operator, data should be convertible to its pointer type.

var id int64
if td.Cmp(t, CreateRecord("test"),
  td.JSON(`{"id": $1, "name": "test"}`, td.Catch(&id, td.NotZero()))) {
  t.Logf("Created record ID is %d", id)
}

It is really useful when used with JSON operator and/or tdhttp helper.

var id int64
ta := tdhttp.NewTestAPI(t, api.Handler).
  PostJSON("/item", `{"name":"foo"}`).
  CmpStatus(http.StatusCreated).
  CmpJSONBody(td.JSON(`{"id": $1, "name": "foo"}`, td.Catch(&id, td.Gt(0))))
if !ta.Failed() {
  t.Logf("Created record ID is %d", id)
}

If you need to only catch data without comparing it, use Ignore operator as expectedValue as in:

var id int64
if td.Cmp(t, CreateRecord("test"),
  td.JSON(`{"id": $1, "name": "test"}`, td.Catch(&id, td.Ignore()))) {
  t.Logf("Created record ID is %d", id)
}

TypeBehind method returns the reflect.Type of expectedValue, except if expectedValue is a TestDeep operator. In this case, it delegates TypeBehind() to the operator, but if nil is returned by this call, the dereferenced reflect.Type of target is returned.

See also Catch godoc.

Example

	t := &testing.T{}

	got := &struct {
		Fullname string `json:"fullname"`
		Age      int    `json:"age"`
	}{
		Fullname: "Bob",
		Age:      42,
	}

	var age int
	ok := td.Cmp(t, got,
		td.JSON(`{"age":$1,"fullname":"Bob"}`,
			td.Catch(&age, td.Between(40, 45))))
	fmt.Println("check got age+fullname:", ok)
	fmt.Println("caught age:", age)

	// Output:
	// check got age+fullname: true
	// caught age: 42