Continue after any IOError while attempting to read image

2 files changed, 10 insertions, 6 deletions

diff --git a/mammoth/docx/files.py b/mammoth/docx/files.py
index ce557f6..bde488d 100644
--- a/mammoth/docx/files.py
+++ b/mammoth/docx/files.py
@@ -22,10 +22,12 @@ class Files(object):
         if _is_absolute(uri):
             return contextlib.closing(urlopen(uri))
         elif self._base is not None:
-            path = os.path.join(self._base, uri)
-            if not os.path.exists(path):
-                raise InvalidFileReferenceError("could not find external image '{0}' from document directory '{1}'".format(uri, self._base))
-            return open(path, "rb")
+            try:
+                return open(os.path.join(self._base, uri), "rb")
+            except IOError as error:
+                message = "could not open external image '{0}' from document directory '{1}'\n{2}".format(
+                    uri, self._base, str(error))
+                raise InvalidFileReferenceError(message)
         else:
             raise InvalidFileReferenceError("could not find external image '{0}', fileobj has no name".format(uri))
 
diff --git a/tests/mammoth_tests.py b/tests/mammoth_tests.py
index aa70c1c..f29ae0f 100644
--- a/tests/mammoth_tests.py
+++ b/tests/mammoth_tests.py
@@ -96,8 +96,10 @@ def warn_if_images_stored_outside_of_document_are_not_found():
         with open(document_path, "rb") as fileobj:
             result = mammoth.convert_to_html(fileobj=fileobj)
             assert_equal("", result.value)
-            expected_warning = "could not find external image 'tiny-picture.png' from document directory '{0}'".format(temp_dir.path)
-            assert_equal([results.warning(expected_warning)], result.messages)
+            expected_warning = "could not open external image 'tiny-picture.png' from document directory '{0}'\n[Errno 2] No such file or directory".format(temp_dir.path)
+            assert_equal("warning", result.messages[0].type)
+            assert result.messages[0].message.startswith(expected_warning), "message was: " + result.messages[0].message
+            assert_equal(1, len(result.messages))
         
 
 @istest