Flutter 测试：如何定位（特定）小部件

Question

I am testing an application created by the mobile apps division.

Hardly any of the widgets have any keys or labels to distinguish themselves from each other.

I'm having a hard timing even targeting a single widget, let alone 2 similar widgets on the same page; example: 2 text field widgets: username, password.

Right now, the only test I have is this:

testWidgets('Empty Login Box', (WidgetTester tester) async {
    app.main();
    
    await tester.pumpAndSettle();
    
    final emailText = find.text("EMAIL");
    expect(emailText, findsOneWidget);
    
    });

And even this doesn't work. Here's the response:

00:40 +0: ...\EndevStudios\MedicalApp\gshDevWork\medical-app-frontend\integration_test\mock_image_upload_test.dart     I00:43 +0: ...\EndevStudios\MedicalApp\gshDevWork\medical-app-frontend\integration_test\mock_image_upload_test.d 2,854ms
00:47 +0: Login Page Tests Empty Login Box
══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════
The following TestFailure was thrown running a test:
Expected: exactly one matching node in the widget tree
  Actual: _TextFinder:<zero widgets with text "EMAIL" (ignoring offstage widgets)>
   Which: means none were found but one was expected

When the exception was thrown, this was the stack:
#4      main.<anonymous closure>.<anonymous closure> (file:///D:/WEBDEV/EndevStudios/MedicalApp/gshDevWork/medical-app-frontend/integration_test/mock_image_upload_test.dart:29:7)
<asynchronous suspension>
<asynchronous suspension>
(elided one frame from package:stack_trace)

This was caught by the test expectation on the following line:
  file:///D:/WEBDEV/EndevStudios/MedicalApp/gshDevWork/medical-app-frontend/integration_test/mock_image_upload_test.dart line 29
The test description was:
  Empty Login Box
════════════════════════════════════════════════════════════════════════════════════════════════════
00:47 +0 -1: Login Page Tests Empty Login Box [E]
  Test failed. See exception logs above.
  The test description was: Empty Login Box

00:48 +0 -1: Some tests failed.

I've been trying to use these CommonFinders class, but I can't seem to utilize them effectively.

https://docs.flutter.dev/cookbook/testing/widget/finders
https://api.flutter.dev/flutter/flutter_driver/CommonFinders-class.html
https://api.flutter.dev/flutter/flutter_test/CommonFinders-class.html

To anyone who can, please help!

Answer 1

You need to first pump your widget, if you don't do that, the Finder is not going to find your widget and will error:

The following TestFailure was thrown running a test: Expected: exactly one matching node in the widget tree Actual: _TextFinder:<zero widgets with text "EMAIL" (ignoring offstage widgets)> Which: means none were found but one was expected

Try the following code:

  testWidgets('Empty Login Box', (WidgetTester tester) async {
    /// Pump your widget first:
    await tester.pumpWidget(const LoginBoxWidget(
      title: 'My Title',
      message: 'Another parameter...',
    )); // Parameters depend on your widget

    final emailText = find.text("EMAIL");
    expect(emailText, findsOneWidget);
  });