`import tvm` now requires pytest

[leandron]

With the merge of #6331, import tvm now requires pytest. I created this issue just to check whether this is something intentional or something that we want to fix.

The chain from import tvm to import pytest happens due to the from .import testing on python/tvm/__init__.py. There is nothing actually done with that import.

https://github.com/apache/incubator-tvm/blob/a4ebb16ed76bfea4ce4eed7be7ea73d4a01027e2/python/tvm/__init__.py#L53-L56

Within python/tvm/testing.py then there is the import pytest. I was thinking that we might want to remove these lines from __init__.py, so that we don't load tvm.testing and will only import it when required. I'm happy to submit a PR removing those lines, in case there is an understanding that it makes sense.

cc @tqchen

[tqchen]

I agree. thanks @leandron ! Please send a PR. cc @tkonolige

[tkonolige]

Good catch.

When I was adding the pytest-related functions, I originally put them in tests/python/__init__.py so they would be local to the tests. Unfortunately, doing this meant that you could no longer run files directly. Instead you'd have to specify the module path. For example, python tests/python/unittest/test_ir_type.py would become python -m tests.python.unittest.test_ir_type.