✅ Enable test case for duplicated headers in test_tutorial/test_header_params/test_tutorial003.py

[Amogha-ark]

Add test coverage for multiple header values in TestClient

Summary

This PR adds test coverage for multiple header values passed as a list of tuples to FastAPI's TestClient, resolving a long-standing TODO comment in the test suite.

Background

The test file tests/test_tutorial/test_header_params/test_tutorial003.py contained a commented-out test case with a TODO comment questioning whether multiple header values were working correctly:

Technical Details

When multiple headers with the same name are passed as a list of tuples like [("x-token", "foo"), ("x-token", "bar")], FastAPI correctly processes them as a list of values ["foo", "bar"]. This is the expected HTTP behavior for multiple headers with the same name.

Type of Change:

• Bug fix
• Test coverage improvement
• New feature
• Breaking change
• Documentation update

Checklist:

• Tests pass locally
• No breaking changes
• Code follows project style guidelines
• Self-review completed

[Amogha-ark]

Hi, I see the PR is failing because of a missing label. I don’t have permission to add it — can someone from the team help with that? Thank you!”

[isgin01]

This is the expected HTTP behavior for multiple headers with the same name.

Thanks for this PR. For reference, you might want to include relevant links next time https://www.rfc-editor.org/rfc/rfc9110.html#section-5.3-1

[YuriiMotov]

This test case covers the use-case described in docs: Duplicate headers.

Don't see anything wrong in enabling it

[tiangolo]

This was probably failing at some point 🤔 Thanks! ☕