add UnmarshalErrors(), solves google#140

errors.go

@@ -15,6 +15,17 @@ func MarshalErrors(w io.Writer, errorObjects []*ErrorObject) error {
 	return json.NewEncoder(w).Encode(&ErrorsPayload{Errors: errorObjects})
 }
 
+// UnmarshalErrors is just a wrapper for convenience
+func UnmarshalErrors(in io.Reader) (*ErrorsPayload, error) {
+	payload := new(ErrorsPayload)
+
+	if err := json.NewDecoder(in).Decode(payload); err != nil {
+		return nil, err
+	}
+
+	return payload, nil
+}
+
 // ErrorsPayload is a serializer struct for representing a valid JSON API errors payload.
 type ErrorsPayload struct {
 	Errors []*ErrorObject `json:"errors"`

errors_test.go

@@ -55,3 +55,98 @@ func TestMarshalErrorsWritesTheExpectedPayload(t *testing.T) {
 		})
 	}
 }
+
+func TestMarshalErrors(t *testing.T) {
+	firstMeta := map[string]interface{}{
+		"custom":     "info",
+		"custom two": "more info",
+	}
+	secondMeta := map[string]interface{}{
+		"foo": "foo info",
+		"bar": "bar info",
+	}
+	sample := map[string]interface{}{
+		"errors": []interface{}{
+			map[string]interface{}{
+				"id":     "1",
+				"title":  "first title",
+				"detail": "first detail",
+				"status": "400",
+				"code":   "first code",
+				"meta":   firstMeta,
+			},
+			map[string]interface{}{
+				"id":     "2",
+				"title":  "second title",
+				"detail": "second detail",
+				"status": "404",
+				"code":   "second code",
+				"meta":   secondMeta,
+			},
+		},
+	}
+
+	data, err := json.Marshal(sample)
+	if err != nil {
+		t.Fatal(err)
+	}
+	in := bytes.NewReader(data)
+
+	errorsPayload, err := UnmarshalErrors(in)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedPayload := ErrorsPayload{
+		Errors: []*ErrorObject{
+			{
+				ID:     "1",
+				Title:  "first title",
+				Detail: "first detail",
+				Status: "400",
+				Code:   "first code",
+				Meta:   &firstMeta,
+			}, {
+				ID:     "2",
+				Title:  "second title",
+				Detail: "second detail",
+				Status: "404",
+				Code:   "second code",
+				Meta:   &secondMeta,
+			},
+		},
+	}
+	if !reflect.DeepEqual(*errorsPayload, expectedPayload) {
+		t.Fatalf("Expected: \n%#v \nto equal: \n%#v", errorsPayload, expectedPayload)
+	}
+}
+
+func TestMarshalErrorsPartialData(t *testing.T) {
+	sample := map[string]interface{}{
+		"errors": []interface{}{
+			map[string]interface{}{
+				"status": "400",
+			},
+			map[string]interface{}{
+				"status": "404",
+			},
+		},
+	}
+
+	data, err := json.Marshal(sample)
+	if err != nil {
+		t.Fatal(err)
+	}
+	in := bytes.NewReader(data)
+
+	errorsPayload, err := UnmarshalErrors(in)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedPayload := ErrorsPayload{Errors: []*ErrorObject{{Status: "400"}, {Status: "404"}}}
+
+	if !reflect.DeepEqual(*errorsPayload, expectedPayload) {
+		t.Fatalf("Expected: \n%#v \nto equal: \n%#v", errorsPayload, expectedPayload)
+	}
+}