a new test runner for blazing-fast tests

docs/topics/testing.rst

@@ -45,9 +45,17 @@ for the full set, but some common ones are:
 
 Our continuous integration server adds some additional flags for other features
 (for example, coverage statistics).  To see what those commands are check out
-the build script at ``/scripts/build.sh``.
+the build script at :src:`scripts/build.sh`.
 
-.. Would be nice to link to the actual script at some point.
+
+Database Setup
+~~~~~~~~~~~~~~
+
+Our test runner will try as hard as it can to skip creating a fresh database
+every time.  If you really want to make a new database (e.g. when models have
+changed), set the environment variable ``FORCE_DB``. ::
+
+    FORCE_DB=true python manage.py test
 
 
 Writing Tests

lib/test_utils/runner.py

@@ -0,0 +1,67 @@
+"""
+This is a test runner that monkeypatches connection.creation to skip database
+creation if it appears that the db already exists.  Your tests will run much
+faster.
+
+To force the normal database creation, define the environment variable
+"FORCE_DB".  It doesn't really matter what the value is, we just check to see
+if it's there.
+"""
+import os
+
+from django.db import connections
+from django.db.backends.creation import TEST_DATABASE_PREFIX
+from django.db.backends.mysql import creation as mysql
+
+import django_nose
+
+
+# XXX: hard-coded to mysql.
+class SkipDatabaseCreation(mysql.DatabaseCreation):
+
+    def _create_test_db(self, verbosity, autoclobber):
+        ### Oh yes, let's copy from django/db/backends/creation.py
+        suffix = self.sql_table_creation_suffix()
+
+        if self.connection.settings_dict['TEST_NAME']:
+            test_database_name = self.connection.settings_dict['TEST_NAME']
+        else:
+            test_database_name = TEST_DATABASE_PREFIX + self.connection.settings_dict['NAME']
+        qn = self.connection.ops.quote_name
+
+        # Create the test database and connect to it. We need to autocommit
+        # if the database supports it because PostgreSQL doesn't allow
+        # CREATE/DROP DATABASE statements within transactions.
+        cursor = self.connection.cursor()
+        self.set_autocommit()
+
+        ### That's enough copying.
+
+        # If we couldn't create the test db, assume it already exists.
+        try:
+            cursor.execute("CREATE DATABASE %s %s" %
+                           (qn(test_database_name), suffix))
+        except Exception, e:
+            print '...Skipping setup of %s!' % test_database_name
+            print '...Try FORCE_DB=true if you need fresh databases.'
+            return test_database_name
+
+        # Drop the db we just created, then do the normal setup.
+        cursor.execute("DROP DATABASE %s %s" %
+                       (qn(test_database_name), suffix))
+        return super(SkipDatabaseCreation, self)._create_test_db(
+            verbosity, autoclobber)
+
+
+class RadicalTestSuiteRunner(django_nose.NoseTestSuiteRunner):
+
+    def setup_databases(self):
+        if not os.getenv('FORCE_DB'):
+            for alias in connections:
+                connection = connections[alias]
+                connection.creation.__class__ = SkipDatabaseCreation
+        return super(RadicalTestSuiteRunner, self).setup_databases()
+
+    def teardown_databases(self, old_config):
+        if os.getenv('FORCE_DB'):
+            super(RadicalTestSuiteRunner, self).teardown_databases(old_config)

scripts/build.sh

@@ -23,6 +23,7 @@ ROOT_URLCONF = 'workspace.urls'
 SETTINGS
 
 echo "Starting tests..."
+export FORCE_DB='yes sir'
 coverage run manage.py test --noinput --logging-clear-handlers --with-xunit
 coverage xml $(find apps lib -name '*.py')
 

settings.py

@@ -184,7 +184,7 @@ DEV_APPS = (
     'django_nose',
 )
 
-TEST_RUNNER = 'django_nose.NoseTestSuiteRunner'
+TEST_RUNNER = 'test_utils.runner.RadicalTestSuiteRunner'
 
 LOG_LEVEL = logging.DEBUG