Add test for standalone driver support of old binary ASTs

Signed-off-by: Nathan Rebours <[email protected]>

test/driver/standalone-supports-old-binary-ast/dune

@@ -0,0 +1,19 @@
+(executable
+ (name identity_standalone)
+ (libraries ppxlib)
+ (modules identity_standalone))
+
+(executable
+ (name print_magic_number)
+ (libraries astlib)
+ (modules print_magic_number))
+
+(cram
+ (enabled_if
+  (or
+   (= %{system} linux)
+   (= %{system} linux_elf)
+   (= %{system} elf)
+   (= %{system} linux_eabihf)
+   (= %{system} linux_eabi)))
+ (deps identity_standalone.exe print_magic_number.exe))

test/driver/standalone-supports-old-binary-ast/identity_standalone.ml

@@ -0,0 +1 @@
+let () = Ppxlib.Driver.standalone ()

test/driver/standalone-supports-old-binary-ast/print_magic_number.ml

@@ -0,0 +1,5 @@
+let magic_length = String.length Astlib.Config.ast_impl_magic_number
+let buf = Bytes.create magic_length
+let len = input stdin buf 0 magic_length
+let s = Bytes.sub_string buf 0 len
+let () = Printf.printf "Magic number: %s" s

test/driver/standalone-supports-old-binary-ast/test.t/run.t

@@ -0,0 +1,14 @@
+Binary AST's of any by ppxlib supported OCaml version are supported.
+The version is preserved.
+
+  $ cat 406_binary_ast | ../print_magic_number.exe
+  Magic number: Caml1999N022
+
+  $ ../identity_standalone.exe --intf 406_binary_ast -o transformed --dump-ast
+  File "_none_", line 1:
+  Error: Internal error: invalid [@@ocaml.ppx.context { load_path }] pair syntax
+  [1]
+
+  $ ../print_magic_number.exe < transformed
+  cannot open transformed: No such file
+  [2]