Fix Breeze --mount-sources tests not mounting local core tests

[sjyangkevin]

What's the issue

From my understanding, breeze ... --mount-sources tests is meant to run local tests against an Airflow installed from a package. For core tests it seems doesn't, because the mount line in scripts/ci/docker-compose/tests-sources.yml has the folder name swapped:

- ../../../core-airflow/tests/:/opt/airflow/core-airflow/tests:cached

As a result:

• Local edits to core tests never reach the container. /opt/airflow/airflow-core/tests keeps the copy baked into the CI image when it was built, and pytest runs that copy.
• Docker creates an empty core-airflow/tests folder in the repo root, because the misspelled host path doesn't exist.

When it was introduced

In #47798 (https://github.com/apache/airflow/pull/47798/changes#diff-c26b9fa407d8179ef67b1cbba03a643a4d8edee5760aae321c273f9b7327966c), which moved the core sources and tests into airflow-core/. The old top-level ../../../tests/:/opt/airflow/tests mount was rewritten and the two words got swapped. This line is the only place the name is spelled that way. It sits outside the block the generate-volumes-for-sources hook regenerates, so nothing caught it.

When it happens

It shows up when you run Breeze with --mount-sources tests (which requires --use-airflow-version), for example to reproduce a provider compatibility run locally as described in contributing-docs/testing/unit_tests.rst, and either:

• you edit or add tests under airflow-core/tests, or
• you edit shared files under airflow-core/tests that every test run loads (unit/dags, unit/plugins, deprecations_ignore.yml), which affects provider tests too.

What you might see then:

• a new test is reported as "not found";
• a fixed test still fails the old way;
• a test you tightened passes, because the old version ran.

Not affected: CI (compatibility jobs use --mount-sources remove), the default selected mode, and provider test folders in this mode, which are mounted correctly.

The fix

Correct the path so local airflow-core/tests is mounted at /opt/airflow/airflow-core/tests, the same as providers-and-tests-sources.yml already does:

- ../../../airflow-core/tests/:/opt/airflow/airflow-core/tests:cached

The pre-commit and manual prek hooks pass on the file, including yamllint and the Docker compose lint. breeze verify lists no local tests for this change.

Screenshots

breeze shell --use-airflow-version 3.3.2 --mount-sources tests --backend sqlite --python 3.11 \
  "cat /opt/airflow/airflow-core/tests/unit/zz_mount_check.txt; ls -d /opt/airflow/core-airflow"

Before (main): the marker isn't visible in the container, and /opt/airflow/core-airflow is created, along with core-airflow/tests on the host.

After (this PR): the marker is visible, and no stray folder is created.

---

Was generative AI tooling used to co-author this PR?

• Yes — Claude Code (Opus 5.5)

Generated-by: Claude Code (Opus 5.5) following the guidelines

[sjyangkevin]

The CI failed due to following 503 will retry later.

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Running command:
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