Managed packages add custom objects, fields, code; QA must verify they work in your org.
Pre-installation:
- Read package documentation.
- Read security review status.
- Check vendor reputation.
Post-installation:
- Verify package installed correctly.
- Permission set / profile assigned to test users.
- Sample features work.
Integration with existing customisations:
- Package fields visible on existing layouts.
- Package automation triggers correctly.
- Package data flows correctly.
Test scenarios:
- Common workflows the package supports.
- Edge cases.
- Performance impact (especially packages with heavy code).
- Conflicts with existing config.
Manage package limits:
- Package code lines (count against limits).
- Package custom objects/fields.
Upgrade testing:
- Vendor releases new version.
- Test in sandbox before production install.
Uninstall testing:
- Document uninstall process.
- Test in sandbox.
Common pitfalls:
- Skipping testing — packages are "trusted".
- Missing customer-specific config that interacts.
- Performance regression.
Senior insight: packages are third-party code. QA them like internal code.