Verify the from email address is set to a valid value

Signed-off-by: Morris Jobke <hey@morrisjobke.de>

isso/config.py

@@ -149,8 +149,21 @@ def load(default, user=None):
             logger.info("Your `session-key` has been stored in the "
                         "database itself, this option is now unused")
 
-    if not parseaddr(parser.get("smtp", "from"))[0]:
-        parser.set("smtp", "from",
-                   formataddr(("Ich schrei sonst!", parser.get("smtp", "from"))))
+    from_address = parser.get("smtp", "from").strip()
+
+    if from_address != '' and parseaddr(from_address) == (None, None):
+        if '@' not in from_address:
+            logger.warn("Your `from` address doesn't contain an @ sign. "
+                        "It is reset to an empty address.")
+            parser.set("smtp", "from", "")
+
+        elif ' ' in from_address:
+            logger.warn("Your `from` address contains a space. "
+                        "It is reset to an empty address.")
+            parser.set("smtp", "from", "")
+
+        else:
+            parser.set("smtp", "from",
+                formataddr(("Ich schrei sonst!", from_address)))
 
     return parser

isso/tests/test_config.py

@@ -30,3 +30,24 @@ class TestConfig(unittest.TestCase):
         self.assertEqual(parser.getlist("foo", "spam"), ['a', 'b', 'cdef'])
         self.assertEqual(list(parser.getiter("foo", "bla")), ['spam', 'ham'])
         self.assertEqual(list(parser.getiter("foo", "asd")), ['fgh'])
+
+    def test_smtp(self):
+
+        cases = [
+            ('"abc" <def@example.org>',     '"abc" <def@example.org>'),
+            ('abc <def@example.org>',       'abc <def@example.org>'),
+            ('"abc def" <def@example.org>', '"abc def" <def@example.org>'),
+            ('abc def <def@example.org>',   'abc def <def@example.org>'),
+            ('def@example.org',             'Ich schrei sonst! <def@example.org>'),
+            ('"abc" def@example.org',       ''),
+            ('"abc"',                       ''),
+            ('abc',                         ''),
+        ]
+
+        for (config_value, expected) in cases:
+            parser = config.IssoParser(allow_no_value=True)
+            parser.read_file(io.StringIO(u"""
+                [smtp]
+                from = """ + config_value))
+
+            self.assertEqual(parser.get("smtp", "from"), expected)