diff --git a/httpie/downloads.py b/httpie/downloads.py
index cf9bf44c..5d6ab50e 100644
--- a/httpie/downloads.py
+++ b/httpie/downloads.py
@@ -59,18 +59,21 @@ def _parse_content_range(content_range, resumed_from):
     # last-byte-pos value, is invalid. The recipient of an invalid
     # byte-content-range- spec MUST ignore it and any content
     # transferred along with it."
-    if (first_byte_pos <= last_byte_pos
-        and (instance_length is None
-             or instance_length <= last_byte_pos)):
+    if (first_byte_pos >= last_byte_pos
+            or (instance_length is not None
+                and instance_length <= last_byte_pos)):
         raise ContentRangeError(
             'Invalid Content-Range returned: %r' % content_range)
 
     if (first_byte_pos != resumed_from
-        or (instance_length is None
-            or last_byte_pos + 1 != instance_length)):
+        or (instance_length is not None
+            and last_byte_pos + 1 != instance_length)):
         # Not what we asked for.
         raise ContentRangeError(
-            'Unexpected Content-Range returned: %r' % content_range)
+            'Unexpected Content-Range returned (%r)'
+            ' for the requested Range ("bytes=%d")'
+            % (content_range, resumed_from)
+        )
 
     return last_byte_pos + 1
 
diff --git a/tests/tests.py b/tests/tests.py
index 0b1b9939..913d340a 100755
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -62,7 +62,7 @@ from httpie.core import main
 from httpie.output import BINARY_SUPPRESSED_NOTICE
 from httpie.input import ParseError
 from httpie.compat import is_windows, is_py26, bytes, str
-
+from httpie.downloads import _parse_content_range, ContentRangeError
 
 CRLF = '\r\n'
 HTTPBIN_URL = os.environ.get('HTTPBIN_URL',
@@ -1421,9 +1421,32 @@ class SessionTest(BaseTestCase):
 
 
 class DownloadsTest(BaseTestCase):
-    # TODO: tests for downloads
-    pass
 
+    # TODO: Download tests
+
+    def test_Content_Range_parsing(self):
+        self.assertEqual(_parse_content_range('bytes 100-199/200', 100), 200)
+        self.assertEqual(_parse_content_range('bytes 100-199/*', 100), 200)
+
+        with self.assertRaises(ContentRangeError):
+            # syntax error
+            _parse_content_range('beers 100-199/*', 100)
+
+        with self.assertRaises(ContentRangeError):
+            # unexpected range
+            _parse_content_range('bytes 100-199/*', 99)
+
+        with self.assertRaises(ContentRangeError):
+            # invalid instance-length
+            _parse_content_range('bytes 100-199/199', 100)
+
+        with self.assertRaises(ContentRangeError):
+            # invalid byte-range-resp-spec
+            _parse_content_range('bytes 100-99/199', 100)
+
+        with self.assertRaises(ContentRangeError):
+            # invalid byte-range-resp-spec
+            _parse_content_range('bytes 100-100/*', 100)
 
 if __name__ == '__main__':
     unittest.main()