Upgrade Django project to Python3 - migrations fail - django

Question

I have a Django project which has been developed with Python2.7, it is currently using Django version 1.10. I am now in the process of upgrading - first to Python3, and then afterwards I will do the Django upgrade.
When I make Python3 virtual environment and run the tests:
venv bash% ./manage.py tests
I get a massive traceback:
Traceback (most recent call last):
File "./manage.py", line 9, in <module>
execute_from_command_line( sys.argv )
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
utility.execute()
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/__init__.py", line 359, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/commands/test.py", line 29, in run_from_argv
super(Command, self).run_from_argv(argv)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/base.py", line 305, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/base.py", line 356, in execute
output = self.handle(*args, **options)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/commands/test.py", line 72, in handle
failures = test_runner.run_tests(test_labels)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/test/runner.py", line 549, in run_tests
old_config = self.setup_databases()
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/test/runner.py", line 499, in setup_databases
self.parallel, **kwargs
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/test/runner.py", line 743, in setup_databases
serialize=connection.settings_dict.get("TEST", {}).get("SERIALIZE", True),
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/backends/base/creation.py", line 70, in create_test_db
run_syncdb=True,
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/__init__.py", line 130, in call_command
return command.execute(*args, **defaults)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/base.py", line 356, in execute
output = self.handle(*args, **options)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line 202, in handle
targets, plan, fake=fake, fake_initial=fake_initial
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/migrations/executor.py", line 97, in migrate
state = self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/migrations/executor.py", line 132, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/migrations/executor.py", line 237, in apply_migration
state = migration.apply(state, schema_editor)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/migrations/migration.py", line 129, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/migrations/operations/models.py", line 96, in database_forwards
schema_editor.create_model(model)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/backends/base/schema.py", line 271, in create_model
self.quote_name(field.column),
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/backends/base/schema.py", line 115, in quote_name
return self.connection.ops.quote_name(name)
File "/home/hove/sleipner/venv/lib/python3.5/site-packages/django/db/backends/sqlite3/operations.py", line 153, in quote_name
if name.startswith('"') and name.endswith('"'):
TypeError: startswith first arg must be bytes or a tuple of bytes, not str
As I understand it the problem is unicode/string issues in the migrations? I have tried to follow the advice: "Add from __future__ import unicode_literals at the top every module". The resulting code still works nicely in Python2.7, but manage.py test fails in the same way for Python3.
For all it is worth the project seems to "basically" work in Python3 when I do:
bash% manage.py runserver
Update:
These are my database settings - might very well be something wrong with this, but observe that it has worked in Python2.7 for many years - and still does:
if "test" in sys.argv:
DATABASES = { 'default' : {
"ENGINE" : "django.db.backends.sqlite3",
"NAME" : "friskby.sqlite",
"TEST" : {
"NAME" : "friskby-test.sqlite"}}}
else:
DATABASE_URL = os.environ.get("DATABASE_URL")
if DATABASE_URL:
config = dj_database_url.config(default = DATABASE_URL)
DATABASES = { 'default': config }
else:
raise Exception("The DATABASE_URL environment variable has not bee set")

Answer 1

The comment from #Will Keeling set me on the right track. My migrations (originally created with Python2.7) had many:
... db_column = b"NAME_OF_COLUMN", ...
statements. I just removed all the leading b - and lo and behold all tests pass in both Python2.7 and Python3.