add unit tests for three uncovered cases

Author: motorina0

test/fixtures/embed.json

@@ -44,6 +44,36 @@
       "arguments": {
         "output": "OP_1 OP_2 OP_ADD"
       }
+    },
+    {
+      "description": "Return value and data do not match",
+      "exception": "Data mismatch",
+      "options": {},
+      "arguments": {
+        "output": "OP_RETURN a3b147dbe4a85579fc4b5a1811e76620560e07267e62b9a0d6858f9127735cadd82f67e06c24dbc4",
+        "data": [
+          "a3b147dbe4a85579fc4b5a1855555555555555555555555555555555555555555555555555555555"
+        ]
+      }
+    },
+    {
+      "description": "Script length incorrect",
+      "exception": "Data mismatch",
+      "options": {},
+      "arguments": {
+        "output": "OP_RETURN a3b1 47db",
+        "data": [
+          "a3b1"
+        ]
+      }
+    },
+    {
+      "description": "Return data is not buffer",
+      "exception": "Output is invalid",
+      "options": {},
+      "arguments": {
+        "output": "OP_RETURN OP_1"
+      }
     }
   ],
   "dynamic": {