rust-testinglisted

# Rust testing (flowmux workspace) Tests split into two worlds. Run the right harness or GUI/D-Bus tests hang or fail spuriously. ## Headless crates — run bare No GTK, no D-Bus. Fast. Default to these while iterating. ```bash cargo test -p flowmux-core cargo test -p flowmux-ipc -- --nocapture cargo test -p flowmux-config cargo test -p flowmux-state ``` ## GTK / D-Bus crates — mirror CI Crates that open GTK or D-Bus (the `flowmux` GUI crate, notifier paths) need a virtual display and a session bus. Mirror CI exactly: ```bash xvfb-run -a dbus-run-session -- cargo test --workspace --locked -- --nocapture ``` - `xvfb-run -a` — headless X server (auto-picks a free display). - `dbus-run-session` — private session bus so `org.gtk.Notifications` tests don't touch the real desktop. - `--locked` — fail if `Cargo.lock` would change (CI parity). ## Single test / filter `cargo test` takes a substring filter: ```bash cargo test -p flowmux-core title_is_shell_cwd_echo # one test by name cargo test -p flowmux-core pane_tree # all matching substring cargo test -p flowmux-core -- --exact path::to::test # exact path cargo test -p flowmux-core -- --ignored # run #[ignore]d ones ``` `-- --nocapture` shows `println!`/`dbg!` output; `-- --test-threads=1` serializes when a test touches shared global/env state. ## Writing tests — house style - **Unit tests inline** under `#[cfg(test)] mod tests { … }` at the bottom of the file (see `flowmux-core/src/li