How to mock Flutter Fire Firebase Functions correctly? - flutter

Question

I'm trying to mock the Firebase Functions package from Flutter Fire, but I keep getting errors.
This is my attempt at creating the Mock. But the call function is giving me errors when I try to override it because the return type is not correct.
library firebase_cloud_functions_mock;
import 'dart:convert';
import 'package:cloud_functions/cloud_functions.dart';
import 'package:mockito/mockito.dart';
class MockFirebaseFunctions extends Mock implements FirebaseFunctions {
final Map<String, String> _jsonStore = <String, String>{};
String _convertMapToJson(Map<String, dynamic> parameters) {
return json.encode(parameters);
}
void mockResult(
{String functionName, String json, Map<String, dynamic> parameters}) {
if (parameters?.isNotEmpty != null) {
// ignore: parameter_assignments
functionName = functionName + _convertMapToJson(parameters);
}
_jsonStore[functionName] = json;
}
String getMockResult(String functionName, Map<String, dynamic> parameters) {
// ignore: parameter_assignments
functionName = parameters == null
? functionName
: (parameters?.isNotEmpty != null
? functionName + _convertMapToJson(parameters)
: functionName);
assert(
_jsonStore[functionName] != null, 'No mock result for $functionName');
return _jsonStore[functionName];
}
#override
HttpsCallable getHttpsCallable({String functionName}) {
return HttpsCallableMock._(this, functionName);
}
}
class HttpsCallableMock extends Mock implements HttpsCallable {
HttpsCallableMock._(this._firebaseFunctions, this._functionName);
final MockFirebaseFunctions _firebaseFunctions;
final String _functionName;
#override
Future<HttpsCallableResult> call([dynamic parameters]) {
final decoded = json.decode(_firebaseFunctions.getMockResult(
_functionName, parameters as Map<String, dynamic>));
return Future.value(HttpsCallableResultMock._(decoded));
}
/// The timeout to use when calling the function. Defaults to 60 seconds.
Duration timeout;
}
class HttpsCallableResultMock extends Mock implements HttpsCallableResult {
HttpsCallableResultMock._(this.data);
/// Returns the data that was returned from the Callable HTTPS trigger.
#override
final dynamic data;
}
Does anyone know how to correctly mock the Firebase Functions package from Flutter Fire?

Answer 1

I was able to make your example work with cloud_function-2.0.0 with three small changes.
Adding the <T> type parameters in HttpsCallableMock.call and
HttpsCallableResultMock.
Replacing the override of
getHttpsCallable with httpsCallable.
Checking parameters?.isNotEmpty == true instead != null. This change might not be needed depending on the behavior you want when empty params are passed.
Here is the updated code.
import 'package:cloud_functions/cloud_functions.dart';
import 'package:mockito/mockito.dart';
class MockFirebaseFunctions extends Mock implements FirebaseFunctions {
final Map<String, String> _jsonStore = <String, String>{};
String _convertMapToJson(Map<String, dynamic> parameters) {
return json.encode(parameters);
}
void mockResult(
{String functionName, String json, Map<String, dynamic> parameters}) {
if (parameters?.isNotEmpty == true) {
functionName = functionName + _convertMapToJson(parameters);
}
_jsonStore[functionName] = json;
}
String getMockResult(String functionName, Map<String, dynamic> parameters) {
// ignore: parameter_assignments
functionName = parameters == null
? functionName
: (parameters?.isNotEmpty == true
? functionName + _convertMapToJson(parameters)
: functionName);
assert(
_jsonStore[functionName] != null, 'No mock result for $functionName. \n Expected one of ${_jsonStore.keys}');
return _jsonStore[functionName];
}
#override
HttpsCallable httpsCallable(String functionName, {HttpsCallableOptions options}) {
return HttpsCallableMock._(this, functionName);
}
}
class HttpsCallableMock extends Mock implements HttpsCallable {
HttpsCallableMock._(this._firebaseFunctions, this._functionName);
final MockFirebaseFunctions _firebaseFunctions;
final String _functionName;
#override
Future<HttpsCallableResult<T>> call<T>([dynamic parameters]) {
final decoded = json.decode(_firebaseFunctions.getMockResult(
_functionName, parameters as Map<String, dynamic>));
return Future.value(HttpsCallableResultMock<T>._(decoded));
}
/// The timeout to use when calling the function. Defaults to 60 seconds.
Duration timeout;
}
class HttpsCallableResultMock<T> extends Mock implements HttpsCallableResult<T> {
HttpsCallableResultMock._(this.data);
/// Returns the data that was returned from the Callable HTTPS trigger.
#override
final T data;
}