improve-coverage

name	improve-coverage
description	Improve code coverage for a Bazel C++ test target or source file
user-invocable	true

Improve Code Coverage

Improve test coverage for a Bazel C++ test target or source file path.

Input Resolution

1. Bazel test target (starts with //, e.g. //src/v/bytes/tests:iobuf_test): use it directly.

2. Source file path (e.g. src/v/bytes/iobuf.cc): find the test target:

   bazel query "kind('.*_test', rdeps(//src/v/..., //$(dirname $FILE):$(basename $FILE .cc), 1))" 2>/dev/null
   

   If multiple targets match, pick the one in the closest tests/ directory. If none match, tell the user and stop.

Workflow

Step 1: Baseline Coverage

Run coverage and read the LLM report:

tools/run-cov <target> -r llm

Note the total line coverage percentage — this is the baseline to beat.

Read the report and identify:

• Uncovered functions — highest impact. One test can cover many lines.
• Partially covered functions — uncovered branches indicate missing error-path or edge-case tests.
• Zero-coverage files in scope — may need new test cases entirely.

Step 2: Understand the Code