Revert "Deprecate raising unittest.SkipTest to skip tests during collection" (#9710)

This reverts commit 25e657bfc1.

Turns out that this *is* a working unittest feature, which pytest should
support, so undo the deprecation.

testing/deprecated_test.py

@@ -86,23 +86,6 @@ def test_private_is_deprecated() -> None:
     PrivateInit(10, _ispytest=True)
 
 
-def test_raising_unittest_skiptest_during_collection_is_deprecated(
-    pytester: Pytester,
-) -> None:
-    pytester.makepyfile(
-        """
-        import unittest
-        raise unittest.SkipTest()
-        """
-    )
-    result = pytester.runpytest()
-    result.stdout.fnmatch_lines(
-        [
-            "*PytestRemovedIn8Warning: Raising unittest.SkipTest*",
-        ]
-    )
-
-
 @pytest.mark.parametrize("hooktype", ["hook", "ihook"])
 def test_hookproxy_warnings_for_pathlib(tmp_path, hooktype, request):
     path = legacy_path(tmp_path)

testing/test_nose.py

@@ -345,7 +345,7 @@ def test_SkipTest_during_collection(pytester: Pytester) -> None:
         """
     )
     result = pytester.runpytest(p)
-    result.assert_outcomes(skipped=1, warnings=1)
+    result.assert_outcomes(skipped=1, warnings=0)
 
 
 def test_SkipTest_in_test(pytester: Pytester) -> None:

testing/test_unittest.py

@@ -1498,3 +1498,30 @@ def test_traceback_pruning(pytester: Pytester) -> None:
     assert passed == 1
     assert failed == 1
     assert reprec.ret == 1
+
+
+def test_raising_unittest_skiptest_during_collection(
+    pytester: Pytester,
+) -> None:
+    pytester.makepyfile(
+        """
+        import unittest
+
+        class TestIt(unittest.TestCase):
+            def test_it(self): pass
+            def test_it2(self): pass
+
+        raise unittest.SkipTest()
+
+        class TestIt2(unittest.TestCase):
+            def test_it(self): pass
+            def test_it2(self): pass
+        """
+    )
+    reprec = pytester.inline_run()
+    passed, skipped, failed = reprec.countoutcomes()
+    assert passed == 0
+    # Unittest reports one fake test for a skipped module.
+    assert skipped == 1
+    assert failed == 0
+    assert reprec.ret == ExitCode.NO_TESTS_COLLECTED