unikernel/duniverse/dune_/test/blackbox-tests/test-cases/watching/quick-cancel.t

@@ -0,0 +1,47 @@
+Modify an input file during the build so that dune interrupts the
+build
+
+  $ . ./helpers.sh
+
+  $ echo "(lang dune 2.0)" > dune-project
+
+  $ cat > x <<EOF
+  > original-contents
+  > EOF
+
+  $ cat >dune <<'EOF'
+  > (rule
+  >  (target y)
+  >  (deps x)
+  >  (action (bash "\> if [[ "$(cat x)" == unstable ]]; then
+  >                "\>   touch ../../go-ahead
+  >                "\>   sleep 1000
+  >                "\>   exit 1
+  >                "\> else
+  >                "\>   cat x > y
+  >                "\> fi
+  > )))
+  > EOF
+
+The rule above makes the test hang if it sees an "unstable" state of
+the file.  This makes it easy to make sure that the dune won't finish
+before we're able to cancel the build.
+
+  $ start_dune
+
+  $ build y
+  Success
+  $ cat _build/default/y
+  original-contents
+
+  $ echo unstable > x
+
+  $ (dune_cmd wait-for-file-to-appear go-ahead; echo new-contents > x) & build y
+  Success
+
+  $ cat _build/default/y
+  new-contents
+
+  $ stop_dune
+  Success, waiting for filesystem changes...
+  Success, waiting for filesystem changes...