run_tests.rst

Run tests

Introduce a Bug

Instead of trying to write new code, let's start by writing a bug!

Diff:

diff --git a/Lib/http/server.py b/Lib/http/server.py
index b1151a2..f132be4 100644
--- a/Lib/http/server.py
+++ b/Lib/http/server.py
@@ -965,6 +965,7 @@ class CGIHTTPRequestHandler(SimpleHTTPRequestHandler):
     rbufsize = 0

     def do_POST(self):
+        bug
         """Serve a POST request.

         This is only implemented for CGI scripts.

Run tests

Type:

$ ./python.exe -m test -v test_httpservers

We expect that tests fail:

(...)
======================================================================
ERROR: test_post (test.test_httpservers.CGIHTTPServerTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File ".../Lib/test/test_httpservers.py", line 726, in test_post
    res = self.request('/cgi-bin/file2.py', 'POST', params, headers)
  File ".../Lib/test/test_httpservers.py", line 79, in request
    return self.connection.getresponse()
  File ".../Lib/http/client.py", line 1322, in getresponse
    response.begin()
  File ".../Lib/http/client.py", line 296, in begin
    version, status, reason = self._read_status()
  File ".../Lib/http/client.py", line 265, in _read_status
    raise RemoteDisconnected("Remote end closed connection without"
http.client.RemoteDisconnected: Remote end closed connection without response

----------------------------------------------------------------------
(...)
FAILED (errors=1)
(...)

Re-run only the failing method:

$ ./python -m test -v -m test_post test_httpservers

Find the code of the failing tests, see most recent call in the traceback:

File ".../Lib/test/test_httpservers.py", line 726, in test_post
  res = self.request('/cgi-bin/file2.py', 'POST', params, headers)

Open Lib/test/test_httpservers.py and go to the respective line (line 726 in this case):

def test_post(self):
    params = urllib.parse.urlencode(
        {'spam' : 1, 'eggs' : 'python', 'bacon' : 123456})
    headers = {'Content-type' : 'application/x-www-form-urlencoded'}
    res = self.request('/cgi-bin/file2.py', 'POST', params, headers)

    self.assertEqual(res.read(), b'1, python, 123456' + self.linesep)

Fix the bug

• Modify Lib/http/server.py to remove bug.
• Re-run test_post() test

Run the whole test suite

• Re-run all test_httpservers tests
• Run the whole test suite

Run the whole test suite:

./python.exe -m test -j0 -rW

Flags:

• -j0: run tests in parallel using as many test processes as your CPU permits
• -r: randomize tests
• -W: hide tests output on success, but show on failure