weldr/tests: Add ability to ignore fields in the response

Certain fields (timestamps, uuids, etc.) are difficult to test for. The
dropFields function allows specific fields to be removed from an
unmarshalled json response body.

internal/weldr/api_test.go

@@ -78,6 +78,36 @@ func sendHTTP(api *weldr.API, external bool, method, path, body string) *http.Re
 	}
 }
 
+// this function serves to drop fields that shouldn't be tested from the unmarshalled json objects
+func dropFields(obj interface{}, fields ...string) {
+	switch v := obj.(type) {
+	// if the interface type is a map attempt to delete the fields
+	case map[string]interface{}:
+		for i, field := range fields {
+			if _, ok := v[field]; ok {
+				delete(v, field)
+				// if the field is found remove it from the fields slice
+				if len(fields) < i-1 {
+					fields = append(fields[:i], fields[i+1:]...)
+				} else {
+					fields = fields[:i]
+				}
+			}
+		}
+		// call dropFields on the remaining elements since they may contain a map containing the field
+		for _, val := range v {
+			dropFields(val, fields...)
+		}
+	// if the type is a list of interfaces call dropFields on each interface
+	case []interface{}:
+		for _, element := range v {
+			dropFields(element, fields...)
+		}
+	default:
+		return
+	}
+}
+
 func testRoute(t *testing.T, api *weldr.API, external bool, method, path, body string, expectedStatus int, expectedJSON string) {
 	resp := sendHTTP(api, external, method, path, body)
 	if resp == nil {