fix(tests): isolate test_project_dependencies from pyproject.toml pollution

[mscolnick]

This pull request was authored by a coding agent.

Fixes marimo-team/ci-agent#27.

test_required_dependencies reads the live on-disk pyproject.toml. Under pytest-xdist, a leaking real uv add from a parallel test can append test-package mid-session (the uv sync step fails without rolling back the file write), flaking the snapshot read.

Cache pyproject.toml contents at tests/conftest.py import time (worker startup, before any test runs) and expose them via a session-scoped pyproject_text fixture.

Test plan

• uv run --group test pytest tests/test_project_dependencies.py -v
• uv run --group test pytest tests/test_project_dependencies.py tests/_runtime/packages/ tests/_server/api/endpoints/test_packages.py -n auto

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	May 21, 2026 12:24am

[cubic-dev-ai]

No issues found across 2 files

Architecture diagram

sequenceDiagram
    participant Pytest as Pytest Worker (xdist)
    participant conftest as conftest.py (import time)
    participant Pyproject as pyproject.toml (on disk)
    participant Fixture as pyproject_text fixture (session-scoped)
    participant Test as test_required_dependencies
    participant Tomlkit as tomlkit library
    participant Snapshot as snapshotter

    Note over Pytest,Snapshot: Worker startup (worker 0..N)
    
    Pytest->>conftest: Import conftest.py
    conftest->>Pyproject: Read pyproject.toml content
    Pyproject-->>conftest: Raw text
    conftest->>conftest: Cache text as _PYPROJECT_TEXT_AT_SESSION_START

    Note over Pytest,Snapshot: Mid-session: parallel test mutates pyproject.toml
    Pytest->>Pyproject: Leaking uv add writes to pyproject.toml
    Pyproject-->>Pytest: File mutated (on disk)

    Note over Pytest,Snapshot: test_required_dependencies execution
    Pytest->>Test: Run test (any worker)
    Test->>Fixture: Request pyproject_text fixture
    Fixture->>conftest: Retrieve cached _PYPROJECT_TEXT_AT_SESSION_START
    conftest-->>Fixture: Cached text (immune to mid-session mutations)
    Fixture-->>Test: pyproject_text string
    Test->>Tomlkit: tomlkit.loads(pyproject_text)
    Tomlkit-->>Test: Parsed pyproject dict
    Test->>Test: Extract and sort dependencies
    Test->>Snapshot: Snapshot dependency list
    Snapshot-->>Test: Snapshot comparison complete
    Test-->>Pytest: Test result (pass/fail)

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_{Re-trigger cubic}

[Copilot]

Pull request overview

This PR fixes flaky dependency snapshot tests under pytest-xdist by preventing mid-session pyproject.toml mutations (e.g., from a leaking uv add) from affecting tests/test_project_dependencies.py reads.

Changes:

• Cache pyproject.toml contents at tests/conftest.py import time and expose them via a session-scoped pyproject_text fixture.
• Update tests/test_project_dependencies.py to parse dependencies from the pyproject_text fixture instead of reading from disk during the test.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tests/conftest.py	Adds a session-scoped pyproject_text fixture backed by import-time cached pyproject.toml contents to avoid xdist-induced flakiness.
tests/test_project_dependencies.py	Switches dependency snapshot tests to use the cached pyproject_text fixture rather than reading pyproject.toml directly.

[github-actions]

🚀 Development release published. You may be able to view the changes at https://marimo.app?v=0.23.7-dev70