yield tests are deprecated in pytest #10728
Description
yield tests are deprecated in pytest and we are getting many warnings in test logs, See e.g.
sklearn/datasets/tests/test_svmlight_format.py::test_load_with_offsets
yield tests are deprecated, and scheduled to be removed in pytest 4.0
sklearn/decomposition/tests/test_online_lda.py::test_verbosity
yield tests are deprecated, and scheduled to be removed in pytest 4.0
sklearn/decomposition/tests/test_pca.py::test_pca_dtype_preservation
yield tests are deprecated, and scheduled to be removed in pytest 4.0
sklearn/ensemble/tests/test_forest.py::test_classification_toy
yield tests are deprecated, and scheduled to be removed in pytest 4.0
sklearn/ensemble/tests/test_forest.py::test_iris
yield tests are deprecated, and scheduled to be removed in pytest 4.0
I think we should get rid of yield.
See pytest-dev/pytest#1714
ping @jnothman @lesteve