add ability to mock images by url

packages/mocktail_image_network/lib/src/mocktail_image_network.dart

@@ -4,6 +4,9 @@ import 'dart:typed_data';
 
 import 'package:mocktail/mocktail.dart';
 
+/// Signature for a function that returns a [Uint8List] for a given [Uri].
+typedef ImageMockProvider = Uint8List Function(Uri uri);
+
 /// {@template mocktail_image_network}
 /// Utility method that allows you to execute a widget test when you pump a
 /// widget that contains an `Image.network` node in its tree.
@@ -41,11 +44,20 @@ import 'package:mocktail/mocktail.dart';
 /// ```
 /// {@endtemplate}
 T mockNetworkImages<T>(T Function() body, {Uint8List? imageBytes}) {
+  return mockNetworkImagesWith(
+    body,
+    provider: (uri) => imageBytes ?? _defaultMockProvider(uri),
+  );
+}
+
+/// {@macro mocktail_image_network}
+T mockNetworkImagesWith<T>(
+  T Function() body, {
+  ImageMockProvider provider = _defaultMockProvider,
+}) {
   return HttpOverrides.runZoned(
     body,
-    createHttpClient: (_) => _createHttpClient(
-      data: imageBytes ?? _transparentPixelPng,
-    ),
+    createHttpClient: (_) => _createHttpClient(provider),
   );
 }
 
@@ -62,14 +74,43 @@ class _MockHttpClientResponse extends Mock implements HttpClientResponse {}
 
 class _MockHttpHeaders extends Mock implements HttpHeaders {}
 
-HttpClient _createHttpClient({required List<int> data}) {
+HttpClient _createHttpClient(ImageMockProvider mockProvider) {
   final client = _MockHttpClient();
+  when(() => client.getUrl(any())).thenAnswer(
+    (invokation) async => _createRequest(
+      invokation.positionalArguments.first as Uri,
+      mockProvider,
+    ),
+  );
+  return client;
+}
+
+HttpClientRequest _createRequest(
+  Uri uri,
+  ImageMockProvider mockProvider,
+) {
   final request = _MockHttpClientRequest();
+  final headers = _MockHttpHeaders();
+  when(() => request.headers).thenReturn(headers);
+  when(request.close).thenAnswer(
+    (invokation) async => _createResponseForUri(uri, mockProvider),
+  );
+
+  return request;
+}
+
+HttpClientResponse _createResponseForUri(
+  Uri uri,
+  ImageMockProvider mockProvider,
+) {
   final response = _MockHttpClientResponse();
   final headers = _MockHttpHeaders();
+
+  final data = mockProvider(uri);
+
   when(() => response.compressionState)
       .thenReturn(HttpClientResponseCompressionState.notCompressed);
-  when(() => response.contentLength).thenReturn(_transparentPixelPng.length);
+  when(() => response.contentLength).thenReturn(data.length);
   when(() => response.statusCode).thenReturn(HttpStatus.ok);
   when(
     () => response.listen(
@@ -85,12 +126,23 @@ HttpClient _createHttpClient({required List<int> data}) {
     return Stream<List<int>>.fromIterable(<List<int>>[data])
         .listen(onData, onDone: onDone);
   });
-  when(() => request.headers).thenReturn(headers);
-  when(request.close).thenAnswer((_) async => response);
-  when(() => client.getUrl(any())).thenAnswer((_) async => request);
-  return client;
+  when(() => response.headers).thenReturn(headers);
+
+  return response;
 }
 
+Uint8List _defaultMockProvider(Uri uri) {
+  final extension = uri.path.split('.').last;
+  return _mockedResponses[extension] ?? _transparentPixelPng;
+}
+
+final _mockedResponses = <String, Uint8List>{
+  'png': _transparentPixelPng,
+  'svg': base64Decode(
+    '''PHN2ZyB3aWR0aD0nMTAwJyBoZWlnaHQ9JzEwMCcgdmlld0JveD0nMCAwIDEgMCAxMDAnIC8+''',
+  ),
+};
+
 final _transparentPixelPng = base64Decode(
   '''iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==''',
 );

packages/mocktail_image_network/test/mocktail_image_network_test.dart

@@ -66,5 +66,27 @@ void main() {
         imageBytes: greenPixel,
       );
     });
+
+    test(
+      'should properly mock svg response and complete without exceptions',
+      () async {
+        await mockNetworkImages(() async {
+          final expectedData = base64Decode(
+            '''PHN2ZyB3aWR0aD0nMTAwJyBoZWlnaHQ9JzEwMCcgdmlld0JveD0nMCAwIDEgMCAxMDAnIC8+''',
+          );
+          final client = HttpClient()..autoUncompress = false;
+          final request = await client.getUrl(Uri.https('', '/image.svg'));
+          final response = await request.close();
+          final data = <int>[];
+
+          response.listen(data.addAll);
+
+          // Wait for all microtasks to run
+          await Future<void>.delayed(Duration.zero);
+
+          expect(data, equals(expectedData));
+        });
+      },
+    );
   });
 }