Issue #15168: Move importlb.test to test.test_importlib.

This should make the Linux distros happy as it is now easier to leave
importlib's tests out of their base Python distribution.

Lib/test/test_importlib/builtin/test_finder.py

@@ -0,0 +1,55 @@
+from importlib import machinery
+from .. import abc
+from .. import util
+from . import util as builtin_util
+
+import sys
+import unittest
+
+class FinderTests(abc.FinderTests):
+
+    """Test find_module() for built-in modules."""
+
+    def test_module(self):
+        # Common case.
+        with util.uncache(builtin_util.NAME):
+            found = machinery.BuiltinImporter.find_module(builtin_util.NAME)
+            self.assertTrue(found)
+
+    def test_package(self):
+        # Built-in modules cannot be a package.
+        pass
+
+    def test_module_in_package(self):
+        # Built-in modules cannobt be in a package.
+        pass
+
+    def test_package_in_package(self):
+        # Built-in modules cannot be a package.
+        pass
+
+    def test_package_over_module(self):
+        # Built-in modules cannot be a package.
+        pass
+
+    def test_failure(self):
+        assert 'importlib' not in sys.builtin_module_names
+        loader = machinery.BuiltinImporter.find_module('importlib')
+        self.assertIsNone(loader)
+
+    def test_ignore_path(self):
+        # The value for 'path' should always trigger a failed import.
+        with util.uncache(builtin_util.NAME):
+            loader = machinery.BuiltinImporter.find_module(builtin_util.NAME,
+                                                            ['pkg'])
+            self.assertIsNone(loader)
+
+
+
+def test_main():
+    from test.support import run_unittest
+    run_unittest(FinderTests)
+
+
+if __name__ == '__main__':
+    test_main()