DEP004 false positive for dev dependencies in test files

[jamesbraza]

Describe the issue

To work around #302, I am un-excluding tests from the current DEFAULT_EXCLUDE like so:

[tool.deptry]
exclude = ["\\.direnv", "\\.git", "\\.venv", "setup\\.py", "venv"]

Secondly, to work around #1531, I have:

[tool.deptry]
optional_dependencies_dev_groups = ["dev"]

These two configurations expose a DEP004 false positive, where now testing dependencies in dev extra are marked like so:

  tests/test_a.py: DEP004 'pytest' imported but declared as a dev dependency

Minimal way to reproduce the issue

Play around with https://github.com/Future-House/ldp/blob/v0.45.1/packages/lmi/pyproject.toml#L40-L75

Expected behavior

Dev dependency imports in test files should not trigger DEP004, since tests are the expected place for dev dependencies to be used.

A possible solution would be to allow mapping directories to dependency groups, so deptry understands that imports in tests/ are expected to use dev dependencies.

Additional context

The workaround is to manually list every dev package in per_rule_ignores for DEP004, which is fragile and defeats the purpose of DEP004.

Environment

• deptry version: 0.25.1
• Python version: 3.13.5
• Operating system (e.g. Ubuntu 22.04, Windows 11): Darwin 25.3.0 arm64

[fpgmaas]

Isn't this basically a duplicate of #302 ? i.e. if deptry would check if all the imports in the tests directory are either in the dependencies, optional dependencies, or under [dependency-groups], this problem would also be solved?

[jamesbraza]

Yeah they're related for sure, both sort of getting at "this directory is expected to use these dependency groups"

• Deptry should detect missing dependencies in tests/ #302 is a feature request for detecting missing dev deps in test dirs
• This issue stems from a workaround for Deptry should detect missing dependencies in tests/ #302 triggering a DEP004 false positive when test directories are un-excluded

Solving #302 would resolve this too yes, so feel free to close this out. However I felt this report could be fixed independently with a narrower scope (avoids a larger redesign #302 requires). Defer to you here