Fixed bug when response is an equality with both sides identical

Author: KarlLundengaard

app/context/symbolic.py

@@ -316,7 +316,12 @@ def equality_equivalence(unused_input):
 
         # TODO: Remove when criteria for checking proportionality is implemented
         if isinstance(res, Equality) and isinstance(ans, Equality):
-            symbols_in_equality_ratio = ((res.args[0]-res.args[1])/(ans.args[0]-ans.args[1])).simplify().free_symbols
+            if (res.args[0]-res.args[1]).simplify() == 0:
+                symbols_in_equality_ratio = (ans.args[0]-ans.args[1]).simplify().free_symbols
+            elif (ans.args[0]-ans.args[1]).simplify() == 0:
+                symbols_in_equality_ratio = (res.args[0]-res.args[1]).simplify().free_symbols
+            else:
+                symbols_in_equality_ratio = ((res.args[0]-res.args[1])/(ans.args[0]-ans.args[1])).simplify().free_symbols
             result = {str(s) for s in symbols_in_equality_ratio}.issubset(parameters_dict["parsing_parameters"]["constants"])
         if result is True:
             return {

app/tests/symbolic_evaluation_tests.py

@@ -1970,5 +1970,24 @@ def test_input_symbols_takes_priority_when_containing_elementary_function_names_
         result = evaluation_function(response, answer, params)
         assert result["is_correct"] is True
 
+    def test_equality_with_both_sides_equal_in_response(self):
+        response = "(1/3)^(1/4)= (1/3)^(1/4)"
+        answer = "Vbar=(1/3)^(1/4)"
+        params = {
+            'atol': 0,
+            'rtol': 0,
+            'strict_syntax': False,
+            'elementary_functions': True,
+            'symbols': {
+                'LtDmax': {'aliases': [''], 'latex': '$(L/D)_{max}$'},
+                'etap': {'aliases': [''], 'latex': '$\\eta_p$'},
+                'sigma': {'aliases': [''], 'latex': '$\\sigma$'},
+                'Vbar': {'aliases': [''], 'latex': '$\\overline{V}$'},
+                'Pbar': {'aliases': [''], 'latex': '$\\overline{P}$'},
+            },
+        }
+        result = evaluation_function(response, answer, params)
+        assert result["is_correct"] is False
+
 if __name__ == "__main__":
     pytest.main(['-xk not slow', "--tb=line", '--durations=10', os.path.abspath(__file__)])