test(melange): augment a test case for ocaml-flags (ocaml#10421)

* test(melange): replace wrong test description

was fixed in ocaml#6953

Signed-off-by: Antonio Nuno Monteiro <anmonteiro@gmail.com>

* test(melange): add an extra test case to ocaml-flags.t

Signed-off-by: Antonio Nuno Monteiro <anmonteiro@gmail.com>

---------

Signed-off-by: Antonio Nuno Monteiro <anmonteiro@gmail.com>

test/blackbox-tests/test-cases/melange/copy-files-include-subdirs.t

@@ -44,7 +44,7 @@ Example using melange.emit, copy_files and include_subdirs
   $ node $src
   hello from file
 
-Now add include_subdirs unqualified to show issue
+Works with `(include_subdirs unqualified)` too
 
   $ echo "(include_subdirs unqualified)" >> src/dune
 

test/blackbox-tests/test-cases/melange/ocaml-flags.t

@@ -29,6 +29,25 @@ Building does not fail, warnings are silenced
   $ node _build/default/output/main.js
   hello
 
+Update dune file to use flags
+
+  $ cat > dune <<EOF
+  > (melange.emit
+  >  (target output)
+  >  (emit_stdlib false)
+  >  (modules main)
+  >  (flags -w -14-26))
+  > EOF
+
+Building should fail as `flags` are not supported in melange emit stanzas
+
+  $ dune build output/main.js
+  File "dune", line 5, characters 2-7:
+  5 |  (flags -w -14-26))
+        ^^^^^
+  Error: Unknown field flags
+  [1]
+
 Update dune file to use ocamlc_flags
 
   $ cat > dune <<EOF