Merge pull request #745 from voussoir/praw-nosectionerror

Add help message for NoSectionError

praw/reddit.py

@@ -14,7 +14,7 @@
 
 from .exceptions import ClientException
 from .config import Config
-from .const import __version__, API_PATH, USER_AGENT_FORMAT
+from .const import __version__, API_PATH, USER_AGENT_FORMAT, configparser
 from .objector import Objector
 from . import models
 
@@ -99,8 +99,22 @@ def __init__(self, site_name=None, **config_settings):
         self._core = self._authorized_core = self._read_only_core = None
         self._objector = None
         self._unique_counter = 0
-        self.config = Config(site_name or os.getenv('praw_site') or 'DEFAULT',
-                             **config_settings)
+
+        try:
+            config_section = site_name or os.getenv('praw_site') or 'DEFAULT'
+            self.config = Config(config_section, **config_settings)
+        except configparser.NoSectionError as exc:
+            help_message = ('You provided the name of a praw.ini '
+                            'configuration which does not exist.\n\nFor help '
+                            'with creating a Reddit instance, visit\n'
+                            'https://praw.readthedocs.io/en/latest/code_overvi'
+                            'ew/reddit_instance.html\n\n'
+                            'For help on configuring PRAW, visit\n'
+                            'https://praw.readthedocs.io/en/latest/getting_sta'
+                            'rted/configuration.html')
+            if site_name is not None:
+                exc.message += '\n' + help_message
+            raise
 
         required_message = ('Required configuration setting {!r} missing. \n'
                             'This setting can be provided in a praw.ini file, '

tests/unit/test_reddit.py

@@ -3,6 +3,7 @@
 import mock
 import pytest
 from praw import __version__, Reddit
+from praw.const import configparser
 from praw.exceptions import ClientException
 
 from . import UnitTest
@@ -117,6 +118,11 @@ def test_reddit__required_settings_set_to_none(self):
                                                  'setting \'{}\' missing.'
                                                  .format(setting))
 
+    def test_reddit__site_name_no_section(self):
+        with pytest.raises(configparser.NoSectionError) as excinfo:
+            Reddit('bad_site_name')
+        assert 'praw.readthedocs.io' in excinfo.value.message
+
     def test_submission(self):
         assert self.reddit.submission('2gmzqe').id == '2gmzqe'