Let’s suppose I have a Django app named MyApp in which I have a Django model called MyModel. This model has a method called process. The database is Postgresql so it allows concurrent queries.

What I need to do is to test if the MyModel.process() method can run simultaneously without problem.

So, in my tests, when I do

class test_smtg(TestCase):
    def setup(self):
        self.my_model = MyModel()
        self.my_model.save()

    def test_single_processing(self):
        self.my_model.process()

It processes successfully. However, when I do this instead:

import threading

class test_smtg(TestCase):
    def setup(self):
        self.my_model = MyModel()
        self.my_model.save()

    def test_concurrent_processing(self):
        thread = threading.Thread(target=self.my_model.process)
        thread.start()

It immediately reports me an error, such that the ID of my_model cannot be found in table myapp_mymodel. Why is that? Why is the program not able to see the object in the database while running on a separated thread? And what can I do to still test if the concurrency works whitout crashing my tests?