Excavator: Migrate Groovy nebula test PalantirJavaFormatPluginTest to the new Java Junit framework

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Changes produced by the roomba/migrate-gradle-testing-junit-framework check.

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Claude Execution Message

Claude finished running successfully.

Perfect! Let me create a summary of what was accomplished:

Migration Complete

I have successfully migrated the test class from PalantirJavaFormatPluginTest.groovy to PalantirJavaFormatPluginTest.java.

Summary of Changes

Key Migration Steps:

1. Added delineator comments to the original Groovy test file to help with human review

2. Converted the test from Groovy/Spock to Java/JUnit 5:

   • Changed test framework from Spock (IntegrationTestKitSpec) to JUnit 5 with @GradlePluginTests annotation
   • Converted @Unroll with Spock's where: block to @ParameterizedTest with @CsvSource
   • Changed test name from string format to snake_case: format_diff_updates_only_lines_changed_in_git_diff

3. File Operations:

   • Used rootProject.gradlePropertiesFile().appendProperty() for setting properties
   • Used rootProject.buildGradle().plugins().add() for plugin management
   • Used rootProject.mainSourceSet().java().writeClass() for creating Java source files
   • Used fileByClassName() to access and modify Java files

4. Git Commands:

   • Created a helper method executeGitCommand() using Java's ProcessBuilder since the framework doesn't provide built-in git support

5. Assertions:

   • Used fluent assertions from GradlePluginTestAssertions.assertThat() for build results
   • Used .assertThat() on file objects for file content assertions

6. Fixed compilation errors:

   • Used proper String.format() syntax with append("%s", variable) to satisfy Error Prone checks
   • Used appendProperty() for properties files as recommended in the testing guide
   • Removed unused imports

The migrated test compiles successfully and follows all best practices outlined in the testing-guide.md. A detailed error log has been created at /repo/test-migration-errors.md documenting all issues encountered and how they were resolved.

Claude Code Metrics

Metric	Value
Total cost	$0.81575335
Total Duration (API)	48
Total Duration (WALL)	10886
Token usage	307287 (input), 381597 (output)

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Migration Notes

Test Migration Errors and Fixes

Migration: PalantirJavaFormatPluginTest.groovy → PalantirJavaFormatPluginTest.java

Initial Compilation Errors

Error 1: Incorrect assertion syntax for file content

Error Message:

error: no suitable method found for assertThat(JavaFile)

Problem:
I tried to use assertThat(rootProject.mainSourceSet().java().fileByClassName("Main")) directly from the GradlePluginTestAssertions class, but there's no overload for JavaFile.

Solution:
According to the testing-guide.md, file assertions should be done by calling .assertThat() on the file object itself, not by passing the file to the assertThat method. Changed:

assertThat(rootProject.mainSourceSet().java().fileByClassName("Main"))
    .hasContent(...)

to:

rootProject.mainSourceSet().java().fileByClassName("Main")
    .assertThat()
    .hasContent(...)

Reference: testing-guide.md section "File Assertions"

Error 2: Error Prone check GradleTestStringFormatting failure

Error Message:

error: An unhandled exception was thrown by the Error Prone static analysis plugin.
BugPattern: GradleTestStringFormatting
java.lang.NullPointerException

Problem:
Used .append(extraGradleProperties) where extraGradleProperties is a parameter variable. The Error Prone check expects String.format() style parameters when passing variables.

Solution:
Changed from:

rootProject.gradlePropertiesFile().append(extraGradleProperties);

to:

rootProject.gradlePropertiesFile().append("%s", extraGradleProperties);

Reference: testing-guide.md mentions "All methods support String.format() syntax for dynamic values" and the Error Prone check enforces this pattern.

Review Pass: Best Practices

Issue 1: Using append() for properties instead of appendProperty()

Problem:
Originally used .append("%s", extraGradleProperties) to add a property to gradle.properties file.

Solution:
According to testing-guide.md, properties files should use appendProperty(key, value) for key-value pairs. Since the parameter value is "palantir.native.formatter=true", I changed to:

rootProject.gradlePropertiesFile().appendProperty("palantir.native.formatter", "true");

Reference: testing-guide.md section "Properties Files" states "Use appendProperty(key, value) for properties files, not append()"

Issue 2: Unused import

Problem:
Import java.util.Collections was not used in the Java version.

Solution:
Removed the unused import.

Migration Strategy Notes

1. Test Name Convention: Changed from Spock string test name 'formatDiff updates only lines changed in git diff' to snake_case format_diff_updates_only_lines_changed_in_git_diff.

2. Parameterized Tests: Used JUnit 5's @ParameterizedTest with @CsvSource instead of Spock's @Unroll with where: block. The framework automatically handles multi-Gradle-version testing, so this parameterization is only for the test-specific parameters (extraGradleProperties and expectedOutput).

3. Git Commands: Since the framework doesn't provide built-in git support, I created a helper method executeGitCommand() that uses Java's ProcessBuilder to run git commands in the project directory.

4. Build File Setup: Converted the Groovy variable standardBuildFile to a helper method that returns GradleFile for fluent chaining, as recommended in the instructions.

5. File Operations:

   • Used rootProject.mainSourceSet().java().writeClass() for creating Java files
   • Used fileByClassName("Main") to access the created file by its class name
   • Used .overwrite() to replace file contents

6. Assertions: Used the fluent assertion API from GradlePluginTestAssertions.assertThat() for result assertions and .assertThat() on file objects for file assertions.

Final State

The test compiles successfully and follows all the best practices outlined in testing-guide.md.

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