[google_maps_flutter] Convert unit tests to Kotlin

[stuartmorgan-g]

Converts google_maps_flutter_android native unit tests from Java to Kotlin.

Similar to my other conversions, the process was:

• Use the Android Studio deterministic auto-conversion.
• Do a bunch of manual cleanup, as separate commits by topic.
  • This included adopting mockito-kotlin to make the mocking much less verbose and complex
• Do a local Gemini review for where the code could be improved as Kotlin code, and address most of that feedback.

This includes a few notable changes that aren't just mockito-kotlin adoption or style/idiom improvement:

• The test-only builders for some Pigeon objects that I introduced when converting the Pigeon generation to Kotlin in an earlier PR have been removed. They were a temporary shim to deal with the fact that Java tests didn't have access to Kotlin features that made builders unnecessary: named parameters, default parameter values, and copy(...) with sparse arguments.
• controller_AddMarkerThrowsErrorIfMarkerIdIsNull was removed because marker ID is non-nullable, so this hasn't been possible since the conversion to Kotlin Pigeon. That was masked by the shim builder previously.
• getBitmapFromBytesThrowsErrorIfInvalidImageData was reworked to do static mocking of BitmapFactory, because it turned out that the Java test was never correct. It was structured as a test-method-level @Test(expected = IllegalArgumentException::class), and the first thing it did was attempt to create the data to trigger the codepath in the plugin by calling Base64.decode with a string that wasn't base 64... which throws an IllegalArgumentException, causing the test to pass before even getting to the intended test code. Fixing that broke the test because it turns out the JUnit environment returns dummy bitmaps for invalid data by default. Mocking the factory allows explicitly forcing the preconditions we need for the test.

Does not include any changes to production code.

Part of flutter/flutter#188630

Pre-Review Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities, or I am not using AI tools.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style, or I have commented below to indicate which documented exception this PR falls under¹.
• I updated/added any relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or I have commented below to indicate which test exemption this PR falls under¹.
• All existing and new tests are passing.

Footnotes

1. Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling. ↩ ↩²

[stuartmorgan-g]

@reidbaker FYI I'm sending this to you because you're still listed as the Android owner in SUGGESTED_REVIEWERS.md; I'm not sure if that's intentional or not.

[gemini-code-assist]

Code Review

This pull request migrates the Android unit tests for the google_maps_flutter_android package from Java to Kotlin. The changes include deleting the Java test files and adding their Kotlin equivalents, as well as adding mockito-kotlin and kotlinx-coroutines-test as test dependencies in build.gradle.kts. There are no review comments, and I have no feedback to provide.

[reidbaker]

@reidbaker FYI I'm sending this to you because you're still listed as the Android owner in SUGGESTED_REVIEWERS.md; I'm not sure if that's intentional or not.

Yeah I can review. I think there is a plan to move ownership but until then I am happy to review