[3.7] bpo-32861: urllib.robotparser fix incomplete __str__ methods. (GH-5711) (GH-6795)

The urllib.robotparser's __str__ representation now includes wildcard
entries and the "Crawl-delay" and "Request-rate" fields.
(cherry picked from commit bd08a0af2d)

Co-authored-by: Michael Lazar <lazar.michael22@gmail.com>

Lib/test/test_robotparser.py

@@ -246,6 +246,33 @@ Disallow: /cyberworld/map/
     bad = ['/cyberworld/map/index.html']
 
 
+class StringFormattingTest(BaseRobotTest, unittest.TestCase):
+    robots_txt = """\
+User-agent: *
+Crawl-delay: 1
+Request-rate: 3/15
+Disallow: /cyberworld/map/ # This is an infinite virtual URL space
+
+# Cybermapper knows where to go.
+User-agent: cybermapper
+Disallow: /some/path
+    """
+
+    expected_output = """\
+User-agent: cybermapper
+Disallow: /some/path
+
+User-agent: *
+Crawl-delay: 1
+Request-rate: 3/15
+Disallow: /cyberworld/map/
+
+"""
+
+    def test_string_formatting(self):
+        self.assertEqual(str(self.parser), self.expected_output)
+
+
 class RobotHandler(BaseHTTPRequestHandler):
 
     def do_GET(self):