[Django]-Why doesn't coverage.py properly measure Django's runserver command?

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Do you get the same problem if you run as follows?

coverage run manage.py runserver --noreload

Without --noreload, another process is started behind the scenes. One process runs the server, the other looks for code changes and restarts the server when changes are made. The chances are, you’re doing the coverage run on the monitoring process rather than the serving process.

Look at django/core/management/commands/runserver.py and django/utils/autoreload.py.

Update: I ran the coverage command, then used ps and lsof to look at what was happening. Here’s what I observed:

ps output:

UID        PID  PPID  C STIME TTY          TIME CMD

vinay    12081  2098  0 16:37 pts/0    00:00:00 /home/vinay/.virtualenvs/watfest/bin/python /home/vinay/.virtualenvs/watfest/bin/coverage run manage.py runserver
vinay    12082 12081  2 16:37 pts/0    00:00:01 /home/vinay/.virtualenvs/watfest/bin/python manage.py runserver

lsof output:

python    12082      vinay    5u     IPv4      48294      0t0        TCP localhost:8000 (LISTEN)

IOW, even before any reloading there are two processes, and the one listening on the TCP port is not the one which coverage is running on.

Here’s what I see with --noreload:

ps output:

UID        PID  PPID  C STIME TTY          TIME CMD

vinay    12140  2098  5 16:44 pts/0    00:00:00 /home/vinay/.virtualenvs/watfest/bin/python /home/vinay/.virtualenvs/watfest/bin/coverage run manage.py runserver --noreload

lsof output:

coverage  12140      vinay    4u     IPv4      51995      0t0        TCP localhost:8000 (LISTEN)

So it’s not obvious why coverage wouldn’t work in the --noreload case. In my very brief test with --noreload, I got coverage of my view code, as shown by the following extract:

festival/__init__   8      7    13%
manage              9      4    56%
settings           33      1    97%
👤Vinay Sajip

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