fix: add monorepo root node_modules to Jest moduleDirectories

[mohammedahmed18]

Summary

• In monorepo setups (e.g., Strapi), workspace packages are hoisted to the root node_modules. When Jest runs from a subpackage, it can't resolve these packages because its default moduleDirectories only includes the local node_modules.
• Adds _find_monorepo_root() detection (looks for yarn.lock, pnpm-workspace.yaml, lerna.json, package-lock.json + node_modules in parent directories) and injects the monorepo root's node_modules into moduleDirectories in the runtime Jest config.
• ~240/1026 Strapi log files showed Cannot find module errors for workspace packages like @strapi/utils, @strapi/types, etc. due to this issue.

Test plan

• Unit tests for _find_monorepo_root() (finds yarn workspace, returns None for standalone)
• Unit tests for _create_runtime_jest_config() (includes moduleDirectories for monorepo, omits for standalone, spreads base config)
• uv run prek passes

🤖 Generated with Claude Code

[claude]

Claude finished @mohammedahmed18's task in 2m 26s —— View job

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PR Review Summary

Checklist

• Triage PR size → SMALL (13 lines of production code)
• Run lint/type checks
• Check stale review threads → none
• Review code changes
• Check for duplicate logic

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Prek Checks

uv run prek run --from-ref origin/main passes cleanly. mypy errors at line 1281 are pre-existing and unrelated to this PR.

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Code Review

Correctness: ✅ Logic is sound

The implementation correctly:

• Calls the pre-existing _find_monorepo_root() helper (already used at 3 other call sites in this file)
• Guards with monorepo_root != project_root to avoid false positives when the project itself has a lock file
• Handles both the base_config_path case (spreads baseConfig.moduleDirectories) and the standalone config case

One bug: module_dirs_line leaks into no-base-config branch (test_runner.py:380)

When base_config_path is None and we're in a monorepo, module_dirs_line is set (the version with baseConfig.moduleDirectories), but the else-branch of if base_config_path: uses module_dirs_line_no_base instead. Both variables are set correctly — this is actually fine. No bug here.

Minor concern: path injection risk

monorepo_node_modules is embedded as a JS string literal using single quotes:

module_dirs_line = f"  moduleDirectories: [...(baseConfig.moduleDirectories || ['node_modules']), '{monorepo_node_modules}'],\n"

If the path contains a single quote (e.g. /home/user's/project/node_modules), the generated JavaScript would be invalid. This is extremely rare in practice but worth a defensive replace("'", "\\'"). Fix this →

package-lock.json as monorepo marker (pre-existing in _find_monorepo_root, not introduced by this PR)

package-lock.json exists in virtually every npm project. A non-monorepo parent directory with package-lock.json + node_modules could be mistaken for a monorepo root. The monorepo_root != project_root guard mitigates the immediate case, but a grandparent with these files would still be picked up as a monorepo root. This is pre-existing behavior, not introduced here.

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Duplicate Detection

No duplicates. _find_monorepo_root already existed and is correctly reused.

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Test Coverage

Tests cover: yarn workspace detection, standalone (returns None), monorepo config with and without base config. Coverage is appropriate for the change.

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Last updated: 2026-03-25T17:08Z