autoUpdateGoldenFiles top-level property
Whether golden files should be automatically updated during tests rather than compared to the image bytes recorded by the tests.
When this is
true, matchesGoldenFile will always report a successful
match, because the bytes being tested implicitly become the new golden.
The Flutter tool will automatically set this to
true when the user runs
flutter test --update-goldens, so callers should generally never have to
explicitly modify this value.
bool autoUpdateGoldenFiles = false;