Adds clauses for specific exceptions in version check (#261)

When any exceptions occurs in the "try" block of the code, it would
handle it the same way regardless.
In the `version_check`, there are 4 possibilities for an error to
occur. These are as follows:
1) Gradio package is installed improperly due to which the version information is inaccessible.
2) JSON cannot be parsed from the Package version URL.
3) JSON that is parsed from the URL does not contain version information.
4) The Package URL is not accessible.

Refactored method to handle these cases and provide appropriate messages.

Co-authored-by: Pradyumna Rahul <pradyumnar@Pradyumnas-MacBook-Pro.local>

gradio/utils.py

@@ -1,3 +1,5 @@
+import json.decoder
+
 import requests
 import pkg_resources
 from distutils.version import StrictVersion
@@ -15,8 +17,15 @@ def version_check():
                     "is available, please upgrade.".format(
                 current_pkg_version, latest_pkg_version))
             print('--------')
-    except:  # TODO(abidlabs): don't catch all exceptions
-        pass
+
+    except pkg_resources.DistributionNotFound:
+        raise RuntimeError("gradio is not setup or installed properly. Unable to get version info.")
+    except json.decoder.JSONDecodeError:
+        raise RuntimeWarning("Unable to parse version details from package URL.")
+    except KeyError:
+        raise RuntimeWarning("Package URL does not contain version info.")
+    except ConnectionError:
+        raise RuntimeWarning("Unable to connect with package URL to collect version info.")
 
 
 def error_analytics(type):

test/test_utils.py

@@ -0,0 +1,46 @@
+from gradio.utils import *
+import unittest
+import pkg_resources
+import unittest.mock as mock
+
+
+class TestUtils(unittest.TestCase):
+    @mock.patch("pkg_resources.require")
+    def test_should_fail_with_distribution_not_found(self, mock_require):
+
+        mock_require.side_effect = pkg_resources.DistributionNotFound()
+
+        with self.assertRaises(RuntimeError) as e:
+            version_check()
+        self.assertEqual(str(e.exception), "gradio is not setup or installed properly. Unable to get version info.")
+
+    @mock.patch("requests.get")
+    def test_should_warn_with_unable_to_parse(self, mock_get):
+
+        mock_get.side_effect = json.decoder.JSONDecodeError("Expecting value", "", 0)
+
+        with self.assertRaises(RuntimeWarning) as e:
+            version_check()
+        self.assertEqual(str(e.exception), "Unable to parse version details from package URL.")
+
+    @mock.patch("requests.get")
+    def test_should_warn_with_connection_error(self, mock_get):
+
+        mock_get.side_effect = ConnectionError()
+
+        with self.assertRaises(RuntimeWarning) as e:
+            version_check()
+        self.assertEqual(str(e.exception), "Unable to connect with package URL to collect version info.")
+
+    @mock.patch("requests.Response.json")
+    def test_should_warn_url_not_having_version(self, mock_json):
+
+        mock_json.return_value = {"foo": "bar"}
+
+        with self.assertRaises(RuntimeWarning) as e:
+            version_check()
+        self.assertEqual(str(e.exception), "Package URL does not contain version info.")
+
+
+if __name__ == '__main__':
+    unittest.main()