Merge branch 'add-crypto-check-example' into 'dev'

Add working example of Crypto.check

See merge request ligolang/ligo!475

src/test/contracts/check_signature.mligo

@@ -1,2 +1,24 @@
 let check_signature (pk, signed, msg : key * signature * bytes) : bool =
   Crypto.check pk signed msg
+
+(*
+$ tezos-client gen keys testsign
+
+$ tezos-client show address testsign -S
+Hash: tz1RffmtWjy435AXZuWwLWG6UaJ66ERmgviA
+Public Key: edpktz4xg6csJnJ5vcmMb2H37sWXyBDcoAp3XrBvjRaTSQ1zmZTeRQ
+Secret Key: unencrypted:edsk34mH9qhMdVWtbammJfYkUoQfwW6Rw5K6rbGW1ajppy3LPNbiJA
+
+$ tezos-client hash data '"hello"' of type string
+Raw packed data: 0x05010000000568656c6c6f
+...
+
+$ tezos-client sign bytes 0x05010000000568656c6c6f for testsign
+Signature: edsigtnzKd51CDomKVMFBoU8SzFZgNqRkYUaQH4DLUg8Lsimz98DFB82uiHAkdvx29DDqHxPf1noQ8noWpKMZoxTCsfprrbs4Xo
+*)
+
+let example : bool =
+  Crypto.check
+    ("edpktz4xg6csJnJ5vcmMb2H37sWXyBDcoAp3XrBvjRaTSQ1zmZTeRQ" : key)
+    ("edsigtnzKd51CDomKVMFBoU8SzFZgNqRkYUaQH4DLUg8Lsimz98DFB82uiHAkdvx29DDqHxPf1noQ8noWpKMZoxTCsfprrbs4Xo" : signature)
+    0x05010000000568656c6c6f

src/test/integration_tests.ml

@@ -2084,6 +2084,7 @@ let check_signature_mligo () : unit result =
                             e_bytes_string "hello world"] in
   let make_expected = e_bool true in
   let%bind () = expect_eq program "check_signature" make_input make_expected in
+  let%bind () = expect_eq_evaluate program "example" (e_bool true) in
   ok ()
 
 let check_signature_religo () : unit result =