mode: “agent” description: “Rename a C++ unit test file to an In-Process Browser Test in Chromium.”

Chromium Code Refactoring: Rename Unit Test to Browser Test

You are an AI assistant with 10 years of experience writing Chromium unit tests and browser tests. Your task is to start refactoring the C++ test file ${file} from a unit test to an In-Process Browser Test by renaming the file and updating the corresponding BUILD.gn file.

Step by step instructions

[ ] 1. Review user input
[ ] 2. Find the right `BUILD.gn` file
[ ] 3. Consider updating the `BUILD.gn` file
[ ] 4. Wait for the user to confirm they have updated the `BUILD.gn` file
[ ] 5. Rename Test File
[ ] 6. Tell the user to format, stage and commit the changes
[ ] 7. Tell the user to proceed to refactoring part 2

Review user input

Review the following information before messaging the user so you can help them effectively.

You are responsible for determining the following variables:

  • ${out_dir}: The build directory (e.g., out/debug_x64).

  • The user may launch this prompt with syntax such as out/debug_x64, if they do you should parse the input into the above variables.

  • The user may have specified ## Developer Prompt Variables. If they have, you should that as the ${out_dir} unless the user respecified it above.

If the user did not provide satisfactory input

  • If the user did not provide input, or provided some input, but did not provide satisfactory input, to know ${out_dir} . You can let them know that they can add the following code block to their copilot-instructions.md file to set the default ${out_dir}.
    ## Developer Prompt Variables
`${out_dir}` = `debug_x64`

Find the right BUILD.gn file

You will need to find the file that references the test file you are refactoring. You can find this with the following command: gn refs out/{out_dir} ${file}

  • If the output is //chrome/browser/foo:bar, the file will be chrome/browser/foo/BUILD.gn and inside of the ${target} bar. You do not need to search for the BUILD.gn file, you can open it directly since chrome is accessible relative to this file at `../../chrome/.

Rename Test File

You must use git mv to rename the test file ${file}.

  • The new filename should replace the _unittest.cc suffix with _browsertest.cc.
  • Example: If ${file} is foo_unittest.cc, the command would be git mv foo_unittest.cc foo_browsertest.cc.

Consider updating the BUILD.gn file

Check the file length of the BUILD.gn file you found in the previous step.

  • You must do this using (Get-Content ${file}).Count

If the file is under 4000 lines

You should attempt to follow the instructions below to update the BUILD.gn file yourself.

If the file is over 4000 lines

If the file is over 4000 lines, tell the user the file is too long for your context window. Tell the user they need to manually update the BUILD.gn file since its too long for your context window.

Updating the BUILD.gn file

When refactoring a unit test to a browser test in Chromium, you will need to update the BUILD.gn file. This is a critical step because the build system needs to know that your test file has moved from the unit tests target to the browser tests target.

You will need to explain your chain of thought and follow these step by step:

[ ] 1. Find your original test file in the unit_tests section
[ ] 2. Remove the entry from unit_tests
[ ] 3. Add to browser_tests
[ ] 4. Review modified lines

Find your original test file in the ${target} section

  • Look for your original file path in the the ${target}, this will likely be a test("unit_tests") or source_set("...unit_tests") section
  • The file path will be formatted as a relative path, like: "../browser/path/to/your_unittest.cc"
  • For example, if your original file was at chrome/browser/ui/views/my_feature_unittest.cc, you'd look for "../browser/ui/views/my_feature_unittest.cc" in the sources list
  • you can tell them the name of the file they are looking for

Remove the file entry from unit_tests

  • Delete the file entry only line from the sources = [ ... ] list in the ${target} section
  • Do not delete the entire sources = [ ... ] block, just the line with your original test file
  • For example, if you are removing the line: ../browser/ui/views/my_feature_unittest_2.cc,
    # Before
# sources = [
#   ...,
#   "../browser/ui/views/my_feature_unittest_1.cc",
#   "../browser/ui/views/my_feature_unittest_2.cc",
#   "../browser/ui/views/my_feature_unittest_3.cc",
#   ...,
# ]
# After
sources = [
  ...,
  "../browser/ui/views/my_feature_unittest_1.cc",
  "../browser/ui/views/my_feature_unittest_3.cc",
  ...,
]

Find the location to add the new browser test

  • Look for the browser_tests section in the same BUILD.gn file
  • This will likely be a test("browser_tests") or source_set("...browser_tests") section
  • If you don't see a browser_tests section, you may need to create one and hook it up to chrome/test/BUILD.gn.
  • Pay attention to any if statement blocks that might be surrounding your test file
  • If your original file was inside a conditional block like if (is_win) or if (enable_extensions), make sure to add your new browsertest file in the corresponding conditional block in the browser_tests section

Add to browser_tests

  • You must add a new line with your renamed file path to its sources = [ ... ] list
  • Keep the same relative path format, just change the filename suffix
  • For example, if you removed "../browser/ui/views/my_feature_unittest.cc", you'd add "../browser/ui/views/my_feature_browsertest.cc"

Review modified lines

  • After making these changes, review the modified lines in the BUILD.gn file to ensure they are correct
  • Make sure you have removed the old unit test file and added the new browser test file correctly
  • No other lines should be modified

Before moving on you must wait for the user to confirm that the BUILD.gn file has been code reviewed by the user and updated correctly.

Tell the user to format, stage and commit the changes

After BUILD.gn file has been updated you must run the following commands in the following step by step order:

[ ] 1. `git cl format ${file} [build.gn file]`
[ ] 2. `git add ${file} [build.gn file]`
[ ] 3. `git commit -m "[Bedrock]: Refactor ${file} _unittest to _browsertest"`
[ ] 4. `git cl upload`

Tell the user they must run git cl upload before continuing to part 2 to upload the changes the code review system before continuing the refactor so that code reviewers can clearly disambiguate the changes made in this part of the refactor compared to the base test. There is a bug in gerrit that causes large diffs of moved files to not show up correctly, so we want to upload the changes in two parts to work around this known issue.

Tell the user to proceed to refactoring part 2

After completing the above steps, provide the user with a clickable link to their new file and tell the user to start a new chat and run /refactor_bedrock_part_2 with the new file path.