test(melange): show that .js file emission doesn't respect flags

Signed-off-by: Antonio Nuno Monteiro <[email protected]>

test/blackbox-tests/test-cases/melange/flags-for-emission.t

@@ -0,0 +1,32 @@
+Test compile_flags are passed to JS file emission
+
+  $ cat > dune-project <<EOF
+  > (lang dune 3.13)
+  > (using melange 0.1)
+  > EOF
+
+  $ cat > main.ml <<EOF
+  > let () = Js.log "hello"
+  > EOF
+
+  $ cat > dune <<EOF
+  > (melange.emit
+  >  (target output)
+  >  (emit_stdlib false)
+  >  (modules main)
+  >  (compile_flags :standard --mel-no-version-header))
+  > EOF
+
+  $ dune build @melange
+
+File is generated with the "Generated by Melange" header even though we
+specified the opposite in flags
+
+  $ cat _build/default/output/main.js
+  // Generated by Melange
+  'use strict';
+  
+  
+  console.log("hello");
+  
+  /*  Not a pure module */