Add empty map patch test

src/test/contracts/map.ligo

@@ -29,6 +29,10 @@ function patch_ (var m: foobar) : foobar is block {
   patch m with map [0 -> 5; 1 -> 6; 2 -> 7]
 } with m
 
+function patch_empty (var m : foobar) : foobar is block {
+  patch m with map []
+} with m
+
 function size_ (const m : foobar) : nat is
   block {skip} with (size(m))
 

src/test/contracts/map.mligo

@@ -14,6 +14,9 @@ let rm (m : foobar) : foobar = Map.remove 42 m
 (* Dummy test so that we can add the same test for PascaLIGO *)
 let patch_ (m : foobar) : foobar = Map.literal [ (0, 5) ; (1, 6) ; (2, 7) ]
 
+(* Second dummy test, see above *)
+let patch_empty (m : foobar) : foobar = Map.literal [ (0, 0) ; (1, 1) ; (2, 2) ]
+
 let size_ (m : foobar) : nat = Map.size m
 
 let gf (m : foobar) : int = Map.find 23 m

src/test/integration_tests.ml

@@ -416,6 +416,11 @@ let map_ type_f path : unit result =
     let expected = ez [(0, 5) ; (1, 6) ; (2, 7)] in
     expect_eq program "patch_" input expected
   in
+  let%bind () =
+    let input = ez [(0,0) ; (1,1) ; (2,2)] in
+    let expected = ez [(0,0) ; (1,1) ; (2,2)] in
+    expect_eq program "patch_empty" input expected
+  in
   let%bind () =
     let make_input = fun n -> ez List.(map (fun x -> (x, x)) @@ range n) in
     let make_expected = e_nat in