add modules_without_implementation tests

Signed-off-by: Rudi Grinberg <[email protected]>

test/blackbox-tests/test-cases/github3766.t/run.t

@@ -86,3 +86,91 @@ A single test case is in test.ml
   % OCAMLPATH=_build/install/default/lib dune exec --build-dir=_b2 ./exe/b.exe
   exe working
 
+
+  $ ./test.exe mli_only_no_stubs --mli-only <<EOF
+  > (library
+  >  (public_name foo)
+  >  (modules_without_implementation foo))
+  > EOF
+  -> creating dune-project
+  # build the library and see if .a is present
+  -> creating dune
+  -> creating mli_only_no_stubs.mli
+  % dune build --root . @install
+  File "lib/dune", line 3, characters 33-36:
+  3 |  (modules_without_implementation foo))
+                                       ^^^
+  Error: Module Foo doesn't exist.
+  [1]
+  % ls _build/install/default/lib/foo/*.a
+  ls: _build/install/default/lib/foo/*.a: No such file or directory
+  [1]
+  
+  # create a dummy executable to test
+  -> creating dune
+  -> creating b.ml
+  
+  # make sure that this library is usable locally
+  % dune exec ./exe/b.exe
+  File "lib/dune", line 3, characters 33-36:
+  3 |  (modules_without_implementation foo))
+                                       ^^^
+  Error: Module Foo doesn't exist.
+  [1]
+
+  # make sure that this library is usable externally
+  % rm -rf lib
+  % OCAMLPATH=_build/install/default/lib dune exec --build-dir=_b2 ./exe/b.exe
+  File "exe/dune", line 5, characters 12-15:
+  5 |  (libraries foo))
+                  ^^^
+  Error: Library "foo" not found.
+  Hint: try:
+    dune external-lib-deps --missing --build-dir _b2 ./exe/b.exe
+  [1]
+
+
+  $ ./test.exe mli_only_no_stubs --mli-only --stub baz <<EOF
+  > (library
+  >  (public_name foo)
+  >  (foreign_stubs (language c) (names baz))
+  >  (modules_without_implementation foo))
+  > EOF
+  -> creating dune-project
+  # build the library and see if .a is present
+  -> creating dune
+  -> creating baz.c
+  -> creating mli_only_no_stubs.mli
+  % dune build --root . @install
+  File "lib/dune", line 4, characters 33-36:
+  4 |  (modules_without_implementation foo))
+                                       ^^^
+  Error: Module Foo doesn't exist.
+  [1]
+  % ls _build/install/default/lib/foo/*.a
+  ls: _build/install/default/lib/foo/*.a: No such file or directory
+  [1]
+  
+  # create a dummy executable to test
+  -> creating dune
+  -> creating b.ml
+  
+  # make sure that this library is usable locally
+  % dune exec ./exe/b.exe
+  File "lib/dune", line 4, characters 33-36:
+  4 |  (modules_without_implementation foo))
+                                       ^^^
+  Error: Module Foo doesn't exist.
+  [1]
+
+  # make sure that this library is usable externally
+  % rm -rf lib
+  % OCAMLPATH=_build/install/default/lib dune exec --build-dir=_b2 ./exe/b.exe
+  File "exe/dune", line 5, characters 12-15:
+  5 |  (libraries foo))
+                  ^^^
+  Error: Library "foo" not found.
+  Hint: try:
+    dune external-lib-deps --missing --build-dir _b2 ./exe/b.exe
+  [1]
+

test/blackbox-tests/test-cases/github3766.t/test.ml

@@ -1,25 +1,31 @@
 open! Stdune
 
+let mli_only = ref false
+
 let stub = ref None
 
 let name = ref ""
 
 let () =
   let anon s = name := s in
   let set_stub s = stub := Some s in
-  let args = [ ("--stub", Arg.String set_stub, "C stub") ] in
+  let args =
+    [ ("--stub", Arg.String set_stub, "C stub")
+    ; ("--mli-only", Arg.Set mli_only, "mli only")
+    ]
+  in
   Arg.parse (Arg.align args) anon "./test.exe <name> [--stub]"
 
 let stub = !stub
 
+let mli_only = !mli_only
+
 let name = !name
 
 let stanza = Io.read_all stdin
 
 let cwd () = Path.external_ (Path.External.cwd ())
 
-(* let dir = Path.relative cwd name *)
-
 let chdir dir = Unix.chdir (Path.to_absolute_filename dir)
 
 let prefix = "test.exe."
@@ -78,7 +84,8 @@ let () =
           in_dir "lib" ~f:(fun () ->
               file "dune" stanza;
               Option.iter stub ~f:(fun name ->
-                  file (name ^ ".c") "void foo() {}"));
+                  file (name ^ ".c") "void foo() {}");
+              if mli_only then file (name ^ ".mli") "type x = unit");
           cmd "dune build --root . @install";
           cmd "ls _build/install/default/lib/foo/*.a");