The following _CastError was thrown resolving an image codec

[alexgrusu43]

I'm trying to test a widget that has a Image.network child.

The following log is provided.

type 'Null' is not a subtype of type 'List<int>' in type cast

When the exception was thrown, this was the stack:
#1      _MockHttpResponse.drain (package:flutter_test/src/_binding_io.dart:364:22)
#2      NetworkImage._loadAsync (package:flutter/src/painting/_network_image_io.dart:99:24)
<asynchronous suspension>
<asynchronous suspension>
(elided 2 frames from dart:async and package:stack_trace)

My test:

testWidgets('My new test', (WidgetTester tester) async {
    mockNetworkImagesFor(() async {
      await tester.pumpWidget(
        MaterialApp(
          home: Scaffold(
            body: ScreenWidget(),
          ),
        ),
      );

      final myImageFinder = find.byKey(const Key('TheImageWidget'));

      expect(myImageFinder, findsOneWidget);

    });
  });

In the above sample of code, ScreenWidget has a child that is a Image.network.

Any thoughts?

[Add00w]

I'm trying to test a widget that has a Image.network child.

The following log is provided.

type 'Null' is not a subtype of type 'List<int>' in type cast

When the exception was thrown, this was the stack:
#1      _MockHttpResponse.drain (package:flutter_test/src/_binding_io.dart:364:22)
#2      NetworkImage._loadAsync (package:flutter/src/painting/_network_image_io.dart:99:24)
<asynchronous suspension>
<asynchronous suspension>
(elided 2 frames from dart:async and package:stack_trace)

My test:

testWidgets('My new test', (WidgetTester tester) async {
    mockNetworkImagesFor(() async {
      await tester.pumpWidget(
        MaterialApp(
          home: Scaffold(
            body: ScreenWidget(),
          ),
        ),
      );

      final myImageFinder = find.byKey(const Key('TheImageWidget'));

      expect(myImageFinder, findsOneWidget);

    });
  });

In the above sample of code, ScreenWidget has a child that is a Image.network.

Any thoughts?

Put await in front of mockNetworkImagesFor as follows:

await mockNetworkImagesFor(() async {
await tester.pumpWidget(
MaterialApp(
home: Scaffold(
body: ScreenWidget(),
),
),
);
......
}