Check for EOF when parsing enums in a .sym file. Fixes #465 (#468)

* Check for EOF when parsing enums in a .sym file. Fixes #465

* Fix test to check for different exception in the python2.7 case

Author: Seneda

src/canmatrix/formats/sym.py

@@ -354,9 +354,12 @@ class Mode(object):
                     while not line[5:].strip().endswith(')'):
                         line = line.split('//')[0]
                         if sys.version_info > (3, 0):  # is there a clean way to to it?
-                            line += ' ' + f.readline().decode(sym_import_encoding).strip()
+                            next_line = f.readline().decode(sym_import_encoding)
                         else:
-                            line += ' ' + next(f).decode(sym_import_encoding).strip()
+                            next_line = next(f).decode(sym_import_encoding)
+                        if next_line is "":
+                            raise EOFError("Reached EOF before finding terminator for enum :\"{}\"".format(line))
+                        line += next_line.strip()
                     line = line.split('//')[0]
                     temp_array = line[5:].strip().rstrip(')').split('(', 1)
                     val_table_name = temp_array[0]

src/canmatrix/tests/test_sym.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 import io
+import sys
 import textwrap
 
 import pytest
@@ -141,3 +142,34 @@ def tests_parse_float(variable_type, bit_length):
     frame = matrix.frames[0]
     signal = frame.signals[0]
     assert signal.is_float
+
+def test_unterminated_enum():
+    f = io.BytesIO(
+        textwrap.dedent(
+            '''\
+            FormatVersion=5.0 // Do not edit this line!
+            Title="Untitled
+            
+            {ENUMS}
+            enum Categories(0="Animal", 1="Vegetable", 3="Mineral"
+            
+            {SENDRECEIVE}
+            
+            [Symbol1]
+            ID=000h
+            DLC=8
+            Var=Signal unsigned 0,16
+            
+            '''
+        ).encode('utf-8'),
+    )
+    # Missing ')' at the end of enum used to cause infinite loop
+
+    matrix = canmatrix.formats.sym.load(f)
+
+    assert len(matrix.load_errors) == 1
+    if sys.version_info > (3, 0):
+        assert isinstance(matrix.load_errors[0], EOFError)
+    else:
+        assert isinstance(matrix.load_errors[0], StopIteration)
+