Add a "syntax_error" key to the result if the test input is invalid

# This should help avoid the need to repeatedly check invalid test strings
# against multiple possible answers.

checker/api.py

@@ -558,15 +558,20 @@ def check(test_str, target_str, symbols=None, check_symbols=True, description=No
         return dict(error="Empty string as argument.")
 
     # Cleanup the strings before anything is done to them:
+    error_is_test = False
     try:
         target_str = parsing.cleanup_string(target_str, reject_unsafe_input=True)
+        error_is_test = True
         test_str = parsing.cleanup_string(test_str, reject_unsafe_input=True)
     except parsing.UnsafeInputException:
         print "ERROR: Input contained non-whitelisted characters!"
-        print "Test string: '%s'" % test_str
+        result = dict(error="Bad input provided!")
+        if error_is_test:
+            print "Test string: '%s'" % test_str
+            result["syntax_error"] = str(True).lower()
         if not _quiet:
             print "=" * 50
-        return dict(error="Bad input provided!")
+        return result
 
     print "Target string: '%s'" % target_str
     print "Test string: '%s'" % test_str
@@ -606,6 +611,7 @@ def check(test_str, target_str, symbols=None, check_symbols=True, description=No
         if not _quiet:
             print "=" * 50
         result["error"] = "Parsing Test Expression Failed!"
+        result["syntax_error"] = str(True).lower()
         return result
 
     result["parsed_target"] = str(target_expr)

checker/unittests.py

@@ -550,6 +550,19 @@ def test_plus_or_minus(self):
         self.assertTrue(response["equality_type"] == "exact", 'For these expressions, expected "equality_type" to be "exact", got "%s"!' % response["equality_type"])
         print "   PASS   ".center(75, "#")
 
+    def test_syntax_error(self):
+        print "\n\n\n" + " Test if Syntax Errors are Reported ".center(75, "#")
+        test_str = "(a + b +"
+        target_str = "a + b"
+        symbols = None
+        response = api.check(test_str, target_str, symbols)
+
+        self.assertTrue("error" in response, 'Expected "error" in response!')
+        self.assertTrue("syntax_error" in response, 'Key "syntax_error" not in response!')
+        print response["syntax_error"], type(response["syntax_error"])
+        self.assertTrue(response["syntax_error"] == "true", 'Expected "syntax_error" to be "true", got "%s"!' % response["syntax_error"])
+        print "   PASS   ".center(75, "#")
+
 #    def test_factorials_limited(self):
 #        print "\n\n\n" + " Test Factorials are correctly Limited ".center(75, "#")
 #        test_str = "factorial(1000)"