Allow to display the generated code in tests

Signed-off-by: Jeremie Dimino <[email protected]>

Author: jeremiedimino

metaquot/test/dune

@@ -1,8 +1,20 @@
 (library
  (name ppx_metaquot_test)
+ (modules test_ppx_metaquot)
  (libraries ppx)
  (preprocess (pps ppx.metaquot)))
 
 (alias
  (name runtest)
  (deps (alias check)))
+
+(alias
+ (name runtest)
+ (deps
+  (:test test.ml)
+  (package ppx))
+ (action (chdir %{project_root}
+          (progn
+           (ignore-outputs
+            (run expect-test %{test}))
+           (diff? %{test} %{test}.corrected)))))

metaquot/test/test.ml

@@ -0,0 +1,19 @@
+#require "astlib"
+#require "ppx.ast"
+
+let loc = Astlib.Location.none
+let () = Clflags.dump_source := true
+[%%expect{|
+val loc : Astlib.Location.t = <abstr>
+|}]
+
+
+[%expr 42]
+[%%expect{|
+
+;;Ppx_ast.V4_07.Expression.create
+    ~pexp_desc:(Ppx_ast.V4_07.Expression_desc.pexp_constant
+                  (Ppx_ast.V4_07.Constant.pconst_integer "42" None))
+    ~pexp_loc:loc ~pexp_attributes:(Ppx_ast.V4_07.Attributes.create []);;
+- : Ppx_ast.V4_07.Expression.t = <abstr>
+|}]

test/expect/expect_test.mll

@@ -132,11 +132,16 @@ let main () =
       let lexbuf = Lexing.from_string s in
       lexbuf.lex_curr_p <- { pos with pos_lnum = 1; };
       let phrases = !Toploop.parse_use_file lexbuf in
-      List.iter phrases ~f:(fun phr ->
-        try
-          ignore (Toploop.execute_phrase true ppf (apply_rewriters phr) : bool)
-        with exn ->
-          Location.report_exception ppf exn
+      List.iter phrases ~f:(function
+        | Parsetree.Ptop_def [] -> ()
+        | phr ->
+          try
+            let phr = apply_rewriters phr in
+            if !Clflags.dump_source then
+              Format.fprintf ppf "%a@?" Pprintast.top_phrase phr;
+            ignore (Toploop.execute_phrase true ppf phr : bool)
+          with exn ->
+            Location.report_exception ppf exn
       );
       Format.fprintf ppf "@?|}]@.");
     Buffer.contents buf)