Cleanup Tests

Description

The goal is to:

• Rename test files to match package file structure
• Move all tests to pytest format
• Split subtests into individual tests or use pytest.mark.parametrize
• Move tests for classes into classes and tests for functions into functions. For example:

  class TestClassName:
      def test_method(self) -> None:
          assert ClassName().method() == something
  
  def test_function() -> None:
      assert module.function() == something
  

In this issue we don't care about the api tests. They are handled in a different project.

For outdated/deprecated modules, such as active learning, we should keep the effort minimal. I would suggest to only make the test filenames match the package file structure. But not change the tests themselves.

See https://github.com/lightly-ai/lightly/blob/master/tests/models/modules/test_memory_bank.py for an example test file.

Tasks

• Cleanup tests for the lightly/transforms subpackage
• Cleanup tests for the lightly/loss subpackage
• Cleanup tests for the lightly/models/modules subpackage
• Cleanup tests for lightly/models/utils.py
• Rename test files for models in lightly/models subpackage
• Cleanup tests for the lightly/data subpackage
• Cleanup tests for the lightly/embedding subpackage
• Cleanup tests for lightly/utils subpackage