added tests to confirm that error is raise when FileLink is passed a directory. Also specifically disallowed passing a file to FileLinks for consistency.

IPython/lib/display.py

@@ -87,7 +87,7 b' class FileLink(object):'
         """
         if isdir(path):
             raise ValueError,\
-             ("Cannot display a directory as a FileLink object. "
+             ("Cannot display a directory using FileLink. "
               "Use FileLinks to display '%s'." % path)
         self.path = path
         self.url_prefix = url_prefix
@@ -171,6 +171,10 b' class FileLinks(FileLink):'
                place, can be passed here to support alternative formatting.
             
         """
+        if isfile(path):
+            raise ValueError,\
+             ("Cannot display a file using FileLinks. "
+              "Use FileLink to display '%s'." % path)
         self.included_suffixes = included_suffixes
         # remove trailing slashs for more consistent output formatting
         path = path.rstrip('/')

IPython/lib/tests/test_display.py

@@ -58,6 +58,12 b' def test_existing_path_FileLink_repr():'
     expected = tf.name
     nt.assert_equal(actual,expected)
 
+def test_error_on_directory_to_FileLink():
+    """FileLink: Raises error when passed directory
+    """
+    td = mkdtemp()
+    nt.assert_raises(ValueError,display.FileLink,td)
+
 #--------------------------
 # FileLinks tests
 #--------------------------
@@ -137,4 +143,11 b' def test_existing_path_FileLinks_repr_alt_formatter():'
     expected.sort()
     # We compare the sorted list of links here as that's more reliable
     nt.assert_equal(actual,expected)
+    
+def test_error_on_file_to_FileLinks():
+    """FileLinks: Raises error when passed file
+    """
+    td = mkdtemp()
+    tf1 = NamedTemporaryFile(dir=td)
+    nt.assert_raises(ValueError,display.FileLinks,tf1.name)