What does "'tests' module incorrectly imported" mean?

I have copied a working test line by line and just changed a few names (at least so I thought) and now I get this very cryptic error: (I have replaced some stuff with FOO, BAR)

    ImportError: 'tests' module incorrectly imported from 'FOO/exports/tests'. Expected 'FOO/exports'. Is this module globally installed?

The problem is that I do not understand the error at all. What does this error message mean?

Complete stacktrace:

    Traceback (most recent call last):
      File "BAR/modeling/manage.py", line 10, in <module>
        execute_from_command_line(sys.argv)
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
        utility.execute()
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/core/management/__init__.py", line 345, in execute
        self.fetch_command(subcommand).run_from_argv(self.argv)
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/core/management/commands/test.py", line 30, in run_from_argv
        super(Command, self).run_from_argv(argv)
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/core/management/base.py", line 348, in run_from_argv
        self.execute(*args, **cmd_options)
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/core/management/commands/test.py", line 74, in execute
        super(Command, self).execute(*args, **options)
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/core/management/base.py", line 399, in execute
        output = self.handle(*args, **options)
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/core/management/commands/test.py", line 90, in handle
        failures = test_runner.run_tests(test_labels)
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/test/runner.py", line 531, in run_tests
        suite = self.build_suite(test_labels, extra_tests)
      File "/Users/jonathan/anaconda/lib/python2.7/site-packages/django/test/runner.py", line 451, in build_suite
        tests = self.test_loader.discover(start_dir=label, **kwargs)
      File "/Users/jonathan/anaconda/lib/python2.7/unittest/loader.py", line 206, in discover
        tests = list(self._find_tests(start_dir, pattern))
      File "/Users/jonathan/anaconda/lib/python2.7/unittest/loader.py", line 267, in _find_tests
        raise ImportError(msg % (mod_name, module_dir, expected_dir))
    ImportError: 'tests' module incorrectly imported from 'FOO/exports/tests'. Expected 'FOO/exports'. Is this module globally installed?

In my experience, weird ImportErrors when running tests are caused by an ImportError in the tests module itself.

Ensure that your tests module can be imported:

    $ python manage.py shell
    ...
    >>> import foo.exports.tests

Edit:

If that causes an error, make sure you do not have both a directory foo/exports/tests and a file foo/exports/tests.py

From: stackoverflow.com/q/37525075