Test impact

Test Impact

Identifies the minimal test set affected by changing a function or module, using codemap-py static analysis — no test execution needed. Result: a ready-to-run pytest command covering only impacted tests.

Two input modes:

• Function-level (module::symbol) — BFS over the reverse call graph; finds every test calling the changed function, directly or transitively. Includes tests mocking the symbol (mock_patches).
• Module-level (bare module) — BFS over the reverse import graph; finds every test importing the module through any chain. Includes tests mocking any symbol in the module.

not_covered: dynamic dispatch, hook callbacks, string-dispatch callers — same blind spot as fn-blast. Surface as a caveat, do not silently drop it.

NOT for: finding all callers of a function (use $codemap-py:query-code fn-blast <module::symbol>); querying module deps or blast radius (use $codemap-py:query-code); running/executing tests (identified here, not executed).

Runtime note

Codex has no bin/ PATH entry and no $CLAUDE_PLUGIN_ROOT-equivalent environment variable. Resolve this skill's installed plugin-root path once, substitute it for PLUGIN_ROOT below, and keep it in reasoning — shell state does not persist across tool calls.

Inputs

<qname> [--no-mocks]:

• qname — module::symbol (function-level) or a bare dotted module (module-level)
• --no-mocks — exclude mock-only test files (no call/import path)
• Omitted → ask in chat which function or module changed, offering: (a) enter module::symbol for function-level, (b) enter a bare module name for module-level, (c) cancel. Wait for the reply before proceeding.

Multi-symbol guard: the invocation text may contain multiple space-separated tokens. Use only the first token as qname; if more than one remains after stripping --no-mocks, warn that test-impact accepts one symbol at a time and that the remaining tokens need a separate invocation each.

Workflow

Step 0 — Ensure index

PLUGIN_ROOT/bin/codemap-py query test-impact "<qname>" [--no-mocks]

If the index is missing:

• SCAN_NO_AUTOBUILD=1 set → report codemap index missing and SCAN_NO_AUTOBUILD=1 — refusing to auto-build. Build it manually first: $codemap-py:scan-codebase and stop.
• otherwise → run PLUGIN_ROOT/bin/codemap-py index --incremental in the foreground first, then retry the query above once.

Step 1 — Parse the JSON result

• test_files — list of test file paths
• pytest_cmd — ready-to-run command
• via_call / via_mock — breakdown of how tests were found
• index.not_covered — surface as a caveat if non-empty
• index.hint — include as a suggestion

Parse JSON explicitly from the CLI's stdout — do not assume the first line of output is the JSON body; log lines may precede or follow it.

Step 2 — Output

total == 0: report "No tests found via static analysis. Try the full suite or search for the symbol name directly under tests/."

total > 0:

## Test impact: <qname>

**Affected tests** (<total> files, <via_call> via call/import graph, <via_mock> via mocks):
<test_files as bullet list>

**Run:**

<pytest_cmd>

<if not_covered non-empty>
**Caveat:** dynamic-dispatch / hook-callback callers are not in the static graph — <hint>.
</if>

Output routing: if total >= 5, write the same content to .reports/codex/codemap-py/test-impact-<YYYY-MM-DD>.md and print the path.