Fix constraints bug.

Add constraints unittests.
Update invalid words.

.vscode/launch.json

@@ -20,6 +20,17 @@
             ],
             "jinja": true,
             "justMyCode": true
+        },
+        {
+            "name": "Python: Debug Tests",
+            "type": "python",
+            "request": "launch",
+            "program": "${file}",
+            "purpose": [
+                "debug-test"
+            ],
+            "console": "integratedTerminal",
+            "justMyCode": false
         }
     ]
 }