Prevent test folder deletion on running flutter create --empty on an existing app project

[victoreronmosele]

This PR modifies the flutter create --empty command to not delete the test/ folder when run on an existing app project.

Before:

flutter create my_app --empty
mkdir my_app/test
if test -d my_app/test; then echo "test exists"; else echo "test does not exist"; fi # test exists
flutter create my_app --empty  
if test -d my_app/test; then echo "test exists"; else echo "test does not exist"; fi # test does not exist

After:

flutter create my_app --empty
mkdir my_app/test
if test -d my_app/test; then echo "test exists"; else echo "test does not exist"; fi # test exists
flutter create my_app --empty  
if test -d my_app/test; then echo "test exists"; else echo "test does not exist"; fi # test exists

Fixes #134928

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• I followed the breaking change policy and added Data Driven Fixes where supported.
• All existing and new tests are passing.

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[andrewkolos]

It looks like this test is missing an assertion

[victoreronmosele]

_createProject implicitly asserts that test/example_test.dart exists but I agree with adding an explicit assertion too.

I will include it.

[andrewkolos]

LGTM

[gspencergoog]

When not creating a new project, won't this recreate test/widget_test.dart if it doesn't exist?

Ideally, this should probably just never write a file to test at all, and skip the delete step.

[andrewkolos]

When not creating a new project, won't this recreate test/widget_test.dart if it doesn't exist?

Indeed, this seems to be the case.

Ideally, this should probably just never write a file to test at all, and skip the delete step.

Agreed.

[andrewkolos]

See #147160 (comment)

[victoreronmosele]

When not creating a new project, won't this recreate test/widget_test.dart if it doesn't exist?

Ideally, this should probably just never write a file to test at all, and skip the delete step.

Agreed. Will make this change.

[victoreronmosele]

I've modified the create command so that when run with --empty, it doesn't write to the test/ directory, for either new or existing projects.

[gspencergoog]

Thanks!! This is much cleaner, and the tests are great.

[gspencergoog]

@andrewkolos Can you re-review this now that it's been updated?

[andrewkolos]

LGTM! Thanks for the continued work on this!