Access Django Test Database - python

I have an API running on Heroku and would like to be able to test it using the test database. My problem I have is that the TestCase setUp(self) method adds the data to an automatically created test database. Then my tests send a POST request to the locally running version of itself. That code then is just using the regular default database instead of the test database the tests are running in.
Here's some code and what I've tried.
In my main settings.py I have named my database like so
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': 'theOneTrueDB',
}
}
And I read here (https://docs.djangoproject.com/en/3.0/topics/testing/overview/#the-test-database) that
The default test database names are created by prepending test_ to the value of each NAME in DATABASES.
So I figured in my views file for one of my apps I could just do
Tenant.objects.using('test_theOneTrueDB').all() and that would work but it says
django.db.utils.ConnectionDoesNotExist: The connection test_theOneTrueDB doesn't exist
I have also tried
Tenant.objects.using('test_default')
and many other things. I am lost. I would also be okay with setting up another database and then using that in the setup with
Tenant.objects.save(using='theOneTrueDBTest)
or something like that.
Any help would be appreciated!
EDIT:
I know have my settings looking like this
DATABASES = {
'default': {
'NAME': 'theOneTrueDB',
'ENGINE': 'django.db.backends.sqlite3',
},
'other': {
'NAME': 'theOneTrueTest',
'ENGINE': 'django.db.backends.sqlite3',
}
}
but then if I try to save to the other database like this
tempPM.save(using='other')
Then I get this error
AssertionError: Database queries to 'other' are not allowed in this test. Add 'other' to API.tests.TenantLogin.databases to ensure proper test isolation and silence this failure.

You don't need to access the test database directly. It will be used by default and you don't need to worry about it.
By default for sqlite3 backend will be used in-memory database, with the name like this file:memorydb_default?mode=memory&cache=shared,
you can examine the settings while tests are running via:
from django.conf import settings
print(settings.DATABASES)

Related

Database config for Django testing

I am building an app using Django and Postgres. I managed to do migrations and I want to test it. When I test with sqlite everything works fine, but when I run tests with postgres I'm getting this error:
Creating test database for alias 'default'...
Got an error creating the test database: permission denied to create database
I've checked user's permissions and I'm sure that this user have permission to create database.
My database config looks like this:
# DATABASES = {
# 'default': {
# 'ENGINE': 'django.db.backends.sqlite3',
# 'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
# }
# }
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': '***',
'USER': '***',
'PASSWORD': '***',
'HOST': '****',
'PORT': '****',
}
}
My postgres db is on a server.
My questions are:
What is the right way to config my db and run tests?
Should I be using sqlite for testing?
If so how my code should look like, so I don't have to comment configs?
It looks like your DB user doesn't have permission to create a new database. Please, take a look here. This command-line utility allows you to create a user and set their permissions.
Example:
createuser my_user --createdb -W --username postgres
Note: you are creating user "my_user" on behalf of PostgreSQL admin role which is postgres by default.
Answering your questions:
You may have several configs for different stages, e.g development, testing, production.
You could use both SQLite and Postgres databases for testing purposes to some extent. You should be awarded, though, if your app relies on some specific features available only in Postgres, then using SQLite for testing doesn't make sense. I personally prefer using the same database for all stages. You could also use docker if you don't want to install DB server on your machine.

Can't apply migrations in Django SQLlite memory database

I'm writing some tests, and I want to be able to run django server with my test settings (that's why I'm using in-memory database).
It seems to be working, no errors reported when running. But migrations are not applied - I can't perform any action on the database, because model tables do not exist.
When I run python manage.py migrate, all my migrations get applied (I see these Applying migrations... OK messages), but it has no effect. When I run python manage.py showmigrations, none of the migrations are applied (I see [ ] 0001_initial etc., without the X).
When I go to django shell, I can't perform any action, because table does not exist. Any idea what might be the reason? It works fine with normal, postgres database.
My settings:
DEBUG = True
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': ':memory:',
'TEST_NAME': ':memory:',
},
}
CACHES = {
'default': {
'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
'LOCATION': ''
}
}

Django refuse to drop PostgreSQL database [another session using the database]

I try to setup postgresql for django, with the following setting:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'tangorblog_features',
'TEST': {
'NAME': 'tangorblog_features'
}
},
}
The idea is to test using development server with selenium and radish-bdd. I will run the development server, and let selenium and Django LiveServerTestCase to test against that server, without creating a separate database. So each time the test run, the database is reset. But Django refuse that there are other session that using the database.
However when I use mysql with the same settings like:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'NAME': 'tangorblog_features',
'HOST': 'localhost',
'PORT': '',
'USER': 'goat',
'PASSWORD': '',
'TEST': {
'NAME': 'tangorblog_features'
}
},
}
The test runs without a problem, about database being used in another session. I think that this is the PostgreSQL problem. How can I tweak it, so it could behave like MySQL?
this happens because mysql and postgres treat database differently. Mysql database is what postgres calls schema. DROP SCHEMA would also happen quetly, just like https://dev.mysql.com/doc/refman/5.7/en/drop-database.html DROP SCHEMA in mysql:
DROP SCHEMA is a synonym for DROP DATABASE.
Differently for postgres you connect to the database to work with schemas, so if smbd wants to drop database you have terminate their sessions. Not like in mysql
Dropping a database does not remove any TEMPORARY tables that were
created in that database. TEMPORARY tables are automatically removed
when the session that created them ends.
which means session is not aborted on database drop.
In order to force database drop and regarding the fact
...it cannot be executed while you or anyone else are connected to the
target database
you have to terminate accordiing backends first, you can do it with
select pg_terminate_backend(pid)
from pg_stat_activity
where datname = 'tangorblog_features';
Of course you have to be connected to some other db yourself

How to add Redis Database in Django-1.9?

I Want to add Redis Database in Django-1.9, so i followed this documents for integration
https://niwinz.github.io/django-redis/latest/
But i didn't find any clue on how to mention Database name in the settings, Here i want to mention Redis as a database on behalf Sqlite3, If uncommented this line django is throwing an Error of DATABASE not found
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'sqlite3'),
}
}
Thanks in Advance for your solution
What's django-redis?
django-redis is a BSD Licensed, full featured Redis cache/session
backend for Django.
What's redis
Redis is an open source (BSD licensed), in-memory data structure
store, used as a database, cache and message broker
Essentially that means django-redis is a django package that allows you to replace the default memcache as django's cache backend and also allows you to replace the DB as the default session storage. However django-redis does not implement features required to use it as a replacement for sqlite3 or any other database.
CACHES = {
"default": {
"BACKEND": "django_redis.cache.RedisCache",
"LOCATION": "redis://127.0.0.1:6379/0",
"OPTIONS": {
"CLIENT_CLASS": "django_redis.client.DefaultClient"
}
}
}
To use the redis database in django you need to add this code to your settings file,based on your requirement you can change the value of the database at the end of LOCATION value like ("redis://127.0.0.1:6379/1") for database '1'.
You can also check here: https://niwinz.github.io/django-redis/latest/#_configure_as_cache_backend
By default Django provides no support for non-relational database backends. However, if you intend to use Redis as your primary database, you can take a look at Django non-rel.

How to read table data from non-default database in Django?

My django project uses 2 databases, 1 existing database and another one which I am creating through my project using Models. I have defined db's in settings.py as below :
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
},
'music': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'myMusicDb.sqlite3'),
}
}
I generated model data using inspectdb command and everything works fine if I remove the default db from settings.py and make the 'music' db the default db. My query is how to keep both db in settings.py and to work with both DataBases ? Is there any way to tell django to use specific database from settings.py ?
I found the answer after reading https://docs.djangoproject.com/en/1.7/topics/db/multi-db/.
We can either use routers or we can make use of using keyword in query such as -
Album.objects.using('music').all()
Thought to post it, may be it could help someone.

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