Testing Notes

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FerricStore tests share process-wide runtime state: app supervision, ETS tables, data directories, LMDB projectors, atomics/counters, and background shard processes.

Rule

Run only one full FerricStore test command at a time from a working tree.

Safe:

mix test apps/ferricstore/test/ferricstore/flow_test.exs

Safe:

mix test apps/ferricstore_server/test

Unsafe:

# two shells at the same time in the same working tree
mix test apps/ferricstore/test
mix test apps/ferricstore_server/test

Why

A single ExUnit run can execute async test modules safely because the suite controls setup and cleanup ordering. Separate mix test processes do not coordinate app shutdown, data directory cleanup, or shared projectors, so they can interfere with each other.

Practical Guidance

  • Use targeted file-level tests while developing.
  • Use one full mix test run before release or large merges.
  • Use separate git worktrees and separate data directories if you need truly parallel full-suite runs.
  • Do not commit generated test data, test-results/, _build/, or deps/.