Add dsa bad test

Author: federicomarra

tests/dsa-bad.slang

@@ -0,0 +1,18 @@
+method main () {
+    var x : Int ;
+    var y : Int ;
+    var z : Int ;
+    assume x >= 0 && y >= 0;
+    z := x - y ;
+    match {
+        z < 0 =>
+            z := z + y ;
+            z := z + 2 * x,
+        true =>
+            z := z - x ;
+            z := z + 4 * y,
+    };
+    // @CheckError
+    assert (z < 0 && z == x - y + 2 * x) || (z >= 0 && z == x - y + 4 * y);
+    assert (z < 0 && z == x - y + y + 2 * x) || (z >= 0 && z == x - y - x + 4 * y)
+}

tests/dsa-test.slang renamed to tests/dsa-good.slang

@@ -3,14 +3,14 @@ method main () {
     var y : Int ;
     var z : Int ;
     assume x >= 0 && y >= 0;
-    z := x -y ;
+    z := x - y ;
     match {
         z < 0 =>
             z := z + y ;
-            z := z + 2 *x,
+            z := z + 2 * x,
         true =>
-            z := z -x ;
-            z := z + 4 *y,
+            z := z - x ;
+            z := z + 4 * y,
     };
-    assert z <= 3 * x && z <= 3 * y && ( z == 3 * x ||z == 3 * y )
+    assert z <= 3 * x && z <= 3 * y && ( z == 3 * x || z == 3 * y )
 }