Two ways to test

examples/test-cw.rs

@@ -31,6 +31,9 @@ struct Args {
 	#[clap(long, default_value = "5000")]
 	timeout: u64,
 
+	#[clap(long)]
+	expect_timeout: bool,
+
 	#[clap(raw = true)]
 	cmd: Vec<String>,
 }
@@ -74,20 +77,26 @@ fn main() -> Result<()> {
 	}
 
 	let start = Instant::now();
-	let mut good = false;
+	let mut timed_out = true;
+	let mut output = None;
 	while start.elapsed() < timeout {
-		if cw.try_wait().into_diagnostic()?.is_some() {
-			good = true;
+		if let Some(out) = cw.try_wait().into_diagnostic()? {
+			timed_out = false;
+			output.replace(out);
 			break;
 		} else {
 			sleep(Duration::from_millis(10));
 		}
 	}
 
+	cw.kill().into_diagnostic()?;
 	tmp_dir.close().into_diagnostic()?;
 
-	if !good {
-		bail!("Timed out");
+	match (timed_out, args.expect_timeout) {
+		(true, false) => bail!("Timed out"),
+		(false, false) => {}
+		(true, true) => eprintln!("{{~expected timeout~}}"),
+		(false, true) => bail!("Expected timeout, but got quit: {:?}", output),
 	}
 
 	Ok(())

tests/trycmd/unix/restart.trycmd

@@ -1,6 +1,9 @@
+This first one tests that test-cw behaves correctly:
+
 ```
 $ test-cw --
 > --quit-after-n 1 -S sh -s 'echo in; sleep 1; echo out'
+? 0
 [[Running `echo in; sleep 1; echo out`]]
 in
 out
@@ -9,9 +12,17 @@ out
 
 ```
 
+
+This one uses `--quit-after-n`. As the default is to restart the command on
+event, we're looking for the second command to start in the middle of the
+first. We ignore the output after the second start because the order of the
+`ForceStop` message and the `in` message can vary. But we're looking for the
+`quit-after-n` signalling message afterwards to check that Cargo Watch stopped.
+
 ```
 $ test-cw --touch File --touch Other --between 500 --
 > --quit-after-n 2 --postpone -S sh -s 'echo in; sleep 1; echo out'
+? 0
 [[Running `echo in; sleep 1; echo out`]]
 in
 [[Running `echo in; sleep 1; echo out`]]
@@ -20,3 +31,22 @@ in
 
 ```
 
+
+This one doesn't use `--quit-after-n`, and instead relies on test-cw to time
+out Cargo Watch. As such, it's similar to the above except that we look for the
+last "success" message from Cargo Watch, and then the expected timeout
+signalling from the tester.
+
+```
+$ test-cw --touch File --touch Other --between 500 --expect-timeout --
+> --postpone -S sh -s 'echo in; sleep 1; echo out'
+? 0
+[[Running `echo in; sleep 1; echo out`]]
+in
+[[Running `echo in; sleep 1; echo out`]]
+...
+[[Command was successful]]
+{~expected timeout~}
+
+```
+