I'm almost starting to wonder if there is some limit on how many TestCases a Django app can have, so I need your help to figure out how to avoid this problem and have functional tests in my app with all of the TestCases.
My Django (v1.10.7) app has 4 fixture TestCases, which run fine. As soon as I add a 5th TestCase with fixtures, running the tests all together with
python3 ./manage.py test myapp
starts resulting in a random one of the old TestCases failing with:
ERROR: setUpClass (myapp.tests.RandomOldTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 206, in _cursor
return self.create_cursor()
File "/usr/lib/python3/dist-packages/django/db/backends/postgresql/base.py", line 211, in create_cursor
cursor = self.connection.cursor()
psycopg2.InterfaceError: connection already closed
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/django/test/testcases.py", line 1019, in setUpClass
'database': db_name,
File "/usr/lib/python3/dist-packages/django/core/management/__init__.py", line 130, in call_command
return command.execute(*args, **defaults)
File "/usr/lib/python3/dist-packages/django/core/management/base.py", line 345, in execute
output = self.handle(*args, **options)
File "/usr/lib/python3/dist-packages/django/core/management/commands/loaddata.py", line 64, in handle
self.loaddata(fixture_labels)
File "/usr/lib/python3/dist-packages/django/core/management/commands/loaddata.py", line 104, in loaddata
self.load_label(fixture_label)
File "/usr/lib/python3/dist-packages/django/core/management/commands/loaddata.py", line 167, in load_label
obj.save(using=self.using)
File "/usr/lib/python3/dist-packages/django/core/serializers/base.py", line 201, in save
models.Model.save_base(self.object, using=using, raw=True, **kwargs)
File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 824, in save_base
updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 889, in _save_table
forced_update)
File "/usr/lib/python3/dist-packages/django/db/models/base.py", line 939, in _do_update
return filtered._update(values) > 0
File "/usr/lib/python3/dist-packages/django/db/models/query.py", line 654, in _update
return query.get_compiler(self.db).execute_sql(CURSOR)
File "/usr/lib/python3/dist-packages/django/db/models/sql/compiler.py", line 1148, in execute_sql
cursor = super(SQLUpdateCompiler, self).execute_sql(result_type)
File "/usr/lib/python3/dist-packages/django/db/models/sql/compiler.py", line 833, in execute_sql
cursor = self.connection.cursor()
File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 233, in cursor
cursor = self.make_cursor(self._cursor())
File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 206, in _cursor
return self.create_cursor()
File "/usr/lib/python3/dist-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/usr/lib/python3/dist-packages/django/utils/six.py", line 685, in reraise
raise value.with_traceback(tb)
File "/usr/lib/python3/dist-packages/django/db/backends/base/base.py", line 206, in _cursor
return self.create_cursor()
File "/usr/lib/python3/dist-packages/django/db/backends/postgresql/base.py", line 211, in create_cursor
cursor = self.connection.cursor()
django.db.utils.InterfaceError: Problem installing fixture '/home/lynoure/PycharmProjects/usertools2/useraccounts/fixtures/test-fixtures.json': connection already closed
It doesn't seem to matter what the new TestCase is, this happens even if I duplicate a pre-existing test with a new name.
In case it matters, this is on Debian Stable, the version of postgresql is 9.6+181, and python3-psycopg2 is 2.6.2-1.