feat: run shell commands asynchronously from command mode

tests/unit/session.rs

@@ -4,6 +4,77 @@ use std::{
     sync::atomic::{AtomicU64, Ordering},
 };
 
+#[cfg(unix)]
+#[test]
+fn shell_commands_leave_editing_live_and_present_both_streams_and_exit_status() {
+    let fixture = Fixture::new();
+    fixture.file("buffer.txt", "source");
+    let mut session = fixture.open("");
+    session.editor.set_project_root(fixture.0.clone());
+    for ch in
+        ":!while [ ! -f release ]; do sleep 0.01; done; pwd; printf 'out'; printf 'err' >&2; exit 7"
+            .chars()
+    {
+        session.handle(Input::Char(ch));
+    }
+    session.handle(Input::Enter);
+    let fixed = Instant::now();
+    session.shell.as_mut().unwrap().2 = fixed;
+    assert!(session.poll_shell_at(fixed + Duration::from_millis(100)));
+    assert_eq!(session.editor.shell_label(), "whi... /");
+    session.execute("!printf should-not-run > unexpected");
+    assert_eq!(
+        session.editor.message(),
+        "A shell command is already running"
+    );
+    assert!(!fixture.0.join("unexpected").exists());
+    session.handle(Input::Char('i'));
+    session.handle(Input::Char('X'));
+    assert_eq!(session.editor.lines(), ["Xsource"]);
+    fixture.file("release", "");
+    drain_until(&mut session, |session| {
+        session.editor.command_output().is_some()
+    });
+    let output = session.editor.command_output().unwrap();
+    assert!(output.title.contains("exit 7"));
+    let text = output.content.lines.join("\n");
+    assert!(text.contains(fixture.0.to_str().unwrap()));
+    assert!(text.ends_with("out\n[stderr]\nerr"), "{text}");
+    assert_eq!(session.editor.shell_label(), "");
+    assert_eq!(session.editor.mode(), Mode::Insert);
+    session.handle(Input::Char('Z'));
+    assert_eq!(session.editor.lines(), ["Xsource"]);
+    session.handle(Input::Escape);
+    session.handle(Input::Char('Y'));
+    assert_eq!(session.editor.lines(), ["XYsource"]);
+    assert_eq!(
+        fs::read_to_string(fixture.0.join("buffer.txt")).unwrap(),
+        "source"
+    );
+}
+
+#[cfg(unix)]
+#[test]
+fn shell_commands_reject_empty_input_and_show_empty_success_without_editing() {
+    let fixture = Fixture::new();
+    fixture.file("buffer.txt", "source");
+    let mut session = fixture.open("");
+    session.execute(":!");
+    assert_eq!(session.editor.message(), "Shell command is empty");
+    assert!(session.shell.is_none());
+    session.execute(":!true");
+    drain_until(&mut session, |session| {
+        session.editor.command_output().is_some()
+    });
+    let output = session.editor.command_output().unwrap();
+    assert_eq!(output.content.lines, ["(no output)"]);
+    assert!(output.title.contains("exit 0"));
+    session.handle(Input::Enter);
+    assert!(session.editor.command_output().is_none());
+    assert_eq!(session.editor.lines(), ["source"]);
+    assert!(!session.editor.dirty());
+}
+
 #[test]
 fn oversized_repository_text_skips_snapshots_and_recovers_after_shrinking() {
     let fixture = Fixture::new();