add reproduction test for #10236 (#10241)

Signed-off-by: Corentin Leruth <[email protected]>

test/blackbox-tests/test-cases/exec-watch/exec-pwd.t/bin/dune

@@ -0,0 +1,2 @@
+(executable
+ (name main))

test/blackbox-tests/test-cases/exec-watch/exec-pwd.t/dune-project

@@ -0,0 +1 @@
+(lang dune 3.6)

test/blackbox-tests/test-cases/exec-watch/exec-pwd.t/run.t

@@ -0,0 +1,25 @@
+  $ export OUTPUT=output.txt
+
+In normal (non-watching) mode, pwd is the folder from which dune is launched
+  $ cd bin
+  $ dune exec --root .. -- pwd > $OUTPUT
+  Entering directory '..'
+  Leaving directory '..'
+  $ cat $OUTPUT
+  $TESTCASE_ROOT/bin
+  $ rm -rf $OUTPUT
+  $ cd ..
+
+While in watch mode, pwd is always the root project folder
+  $ cd bin
+  $ dune exec --root .. -w -- pwd > $OUTPUT &
+  Entering directory '..'
+  Success, waiting for filesystem changes...
+  Leaving directory '..'
+  $ PID=$!
+  $ until test -s $OUTPUT; do sleep 0.1; done;
+  $ kill $PID
+  $ cat $OUTPUT
+  $TESTCASE_ROOT
+  $ rm -rf $OUTPUT
+  $ cd ..