Fix: Preserve moduleNameMapper from TypeScript Jest configs in monorepos

[mohammedahmed18]

Problem

When Jest configs are TypeScript files (.ts), Codeflash's runtime config creation skipped them (cannot require() TypeScript directly) and created a standalone config WITHOUT moduleNameMapper. This caused monorepo workspace packages like @budibase/backend-core to fail with "Cannot find module" errors.

Root Cause

In test_runner.py, _create_runtime_jest_config() had two branches:

1. If base config is .js/.cjs: extends it with require()
2. If base config is .ts: creates standalone config (no moduleNameMapper)

The standalone config only set: roots, testMatch, moduleDirectories, globalSetup/globalTeardown. It did NOT include moduleNameMapper, which is critical for monorepo workspace package resolution.

Solution

1. Added _extract_module_name_mapper_from_ts_config() helper that uses ts-node to load TypeScript configs and extract moduleNameMapper
2. Modified standalone config generation to call this helper and serialize moduleNameMapper into the runtime config
3. Falls back gracefully if extraction fails (logs debug message)

Impact

• Severity: HIGH - Systematic failure on ALL TypeScript monorepo projects
• Scope: 100% reproducible (not transient)
• Affected: budibase, any project with workspace packages like @workspace/*
• Trace IDs: 0130fa38-9ede-4c1f-9369-b54c31f7e938 and 40+ others in budibase logs

Testing

• ✅ Added test_typescript_jest_config_modulemapper.py with 2 comprehensive tests
• ✅ Updated test_javascript_test_runner.py test expectations (PR Fix: Always disable Jest globalSetup/globalTeardown for Codeflash tests #2009 behavior change)
• ✅ All 36 existing + new tests pass
• ✅ No linting/type errors (uv run prek passes)
• ✅ Verified extraction works with real TypeScript configs

Files Changed

• codeflash/languages/javascript/test_runner.py (+154 lines: helper function + config generation logic)
• tests/test_languages/test_typescript_jest_config_modulemapper.py (+122 lines: new test file)
• tests/test_languages/test_javascript_test_runner.py (updated test expectations)

Example

Before (missing moduleNameMapper):

module.exports = {
  roots: ["/workspace/target/packages/server", ...],
  testMatch: ['**/*.test.ts', ...],
  globalSetup: undefined,
  globalTeardown: undefined,
};

After (with moduleNameMapper):

module.exports = {
  roots: ["/workspace/target/packages/server", ...],
  testMatch: ['**/*.test.ts', ...],
  moduleNameMapper: {
    "@budibase/backend-core/(.*)": "<rootDir>/../backend-core/$1",
    "@budibase/backend-core": "<rootDir>/../backend-core/src",
    "@budibase/shared-core": "<rootDir>/../shared-core/src",
  },
  globalSetup: undefined,
  globalTeardown: undefined,
};

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Co-authored-by: Claude Sonnet 4.5 noreply@anthropic.com