diff --git a/src/rosdoc_lite/doxygenator.py b/src/rosdoc_lite/doxygenator.py
index 74b251f..33b28cc 100644
--- a/src/rosdoc_lite/doxygenator.py
+++ b/src/rosdoc_lite/doxygenator.py
@@ -116,9 +116,20 @@ def prepare_tagfiles(tagfile_spec, tagfile_dir, output_subfolder):
         print(tag_pair)
         if tag_pair['location'].find("http://") == 0:
             #We need to download the file from somewhere online
-            import urllib2
             try:
-                ret = urllib2.urlopen(tag_pair['location'])
+                if sys.version_info.major < 3:
+                    # python 2
+                    from urllib2 import urlopen, URLError, HTTPError
+                else:
+                    # python 3
+                    from urllib.request import urlopen
+                    from urllib.error import URLError, HTTPError
+            except ImportError:
+                print("Could not import urllib, skipping", file=sys.stderr)
+                continue
+
+            try:
+                ret = urlopen(tag_pair['location'])
                 if ret.code != 200:
                     print("Could not fetch the tagfile from %s, skipping" % tag_pair['location'], file=sys.stderr)
                     continue
@@ -128,7 +139,7 @@ def prepare_tagfiles(tagfile_spec, tagfile_dir, output_subfolder):
                 tagfile.write(ret.read())
                 tagfile.close()
                 tagfile_string += "%s=%s " % (tagfile_path, get_doc_path(output_subfolder, tag_pair))
-            except (urllib2.URLError, urllib2.HTTPError) as e:
+            except (URLError, HTTPError) as e:
                 print("Could not fetch the tagfile from %s, skipping" % tag_pair['location'], file=sys.stderr)
                 continue
         elif tag_pair['location'].find("file://") == 0:
diff --git a/test/test_doxygenator.py b/test/test_doxygenator.py
index 9fafa1f..1e4c5c3 100644
--- a/test/test_doxygenator.py
+++ b/test/test_doxygenator.py
@@ -1,8 +1,33 @@
+import os
 import unittest
+import sys
+if sys.version_info >= (3, 3):
+    from unittest.mock import patch, mock_open
+else:
+    # Expect the `mock` package for python 2.
+    # https://pypi.python.org/pypi/mock
+    from mock import patch, mock_open
 from rosdoc_lite import doxygenator as doxy
 
+def builtins_name():
+    return "__builtin__.open" if sys.version_info.major < 3 else "builtins.open"
+
+def urlopen_name():
+    return "urllib2.urlopen" if sys.version_info.major < 3 else "urllib.request.urlopen"
+
 class TestGetDocPath(unittest.TestCase):
 
+    def setUp(self):
+        self.tagfile_spec = "test_tagfile_spec.yaml"
+        self.tagfile_dir = "./test_tagfiles"
+        self.output_subfolder = "/path/to/"
+
+    def tearDown(self):
+        if os.path.exists(self.tagfile_spec):
+            os.remove(self.tagfile_spec)
+        if os.path.exists(self.tagfile_dir):
+            os.rmdir(self.tagfile_dir)
+
     def test_relative_doc_path(self):
         tag_pair = {'docs_url':"relative/path"}
         output = doxy.get_doc_path("sub/folders", tag_pair)
@@ -21,3 +46,40 @@ def test_absolute_doc_path(self):
         output = doxy.get_doc_path("sub/folders", tag_pair)
         self.assertEqual("https://absolu.te/path/doxygen_output_folder", output)
 
+    def test_prepare_tagfiles_valid_http_location(self):
+        input_tagfile_spec = "- location: http://example.com/tagfile.yaml\n  docs_url: http://example.com/docs"
+        expected_result = os.path.join(self.tagfile_dir, 'tagfile.yaml') + "=http://example.com/docs "
+        with patch(builtins_name(), mock_open(read_data=input_tagfile_spec)) as _:
+            with patch(urlopen_name()) as mock_urlopen:
+                mock_urlopen.return_value.code = 200
+                mock_urlopen.return_value.read.return_value = b"tagfile_content"
+
+                result = doxy.prepare_tagfiles(self.tagfile_spec, self.tagfile_dir, self.output_subfolder)
+
+                self.assertEqual(result, expected_result)
+
+    def test_prepare_tagfiles_invalid_http_location(self):
+        input_tagfile_spec = "- location: http://example.com/invalid_tagfile.yaml\n  docs_url: http://example.com/docs"
+        with patch(builtins_name(), mock_open(read_data=input_tagfile_spec)) as _:
+            with patch(urlopen_name()) as mock_urlopen:
+                mock_urlopen.return_value.code = 404
+
+                result = doxy.prepare_tagfiles(self.tagfile_spec, self.tagfile_dir, self.output_subfolder)
+
+                self.assertEqual(result, "")
+
+    def test_prepare_tagfiles_valid_file_location(self):
+        input_tagfile_spec = "- location: file:///path/to/tagfile.yaml\n  docs_url: /path/to/docs"
+        expected_result = "/path/to/tagfile.yaml=/path/to/docs "
+
+        with patch(builtins_name(), mock_open(read_data=input_tagfile_spec)) as _:
+            result = doxy.prepare_tagfiles(self.tagfile_spec, self.tagfile_dir, self.output_subfolder)
+
+            self.assertEqual(result, expected_result)
+
+    def test_prepare_tagfiles_invalid_location_prefix(self):
+        input_tagfile_spec = "- location: invalid_prefix://example.com/tagfile.yaml\n  docs_url: http://example.com/docs"
+        with patch(builtins_name(), mock_open(read_data=input_tagfile_spec)) as _:
+            result = doxy.prepare_tagfiles(self.tagfile_spec, self.tagfile_dir, self.output_subfolder)
+
+            self.assertEqual(result, "")