Change more tests to use import_module for the modules that
should cause tests to be skipped.  Also rename import_function
to the more descriptive get_attribute and add a docstring.
diff --git a/Lib/test/test_gdbm.py b/Lib/test/test_gdbm.py
index 76689f0..131d22b 100755
--- a/Lib/test/test_gdbm.py
+++ b/Lib/test/test_gdbm.py
@@ -1,7 +1,8 @@
-import gdbm
 import unittest
 import os
-from test.test_support import verbose, TESTFN, run_unittest, unlink
+from test.test_support import (verbose, TESTFN, run_unittest, unlink,
+    import_module)
+gdbm = import_module('gdbm')
 
 
 filename = TESTFN