Add tests for pickletools.optimize().

Lib/test/test_pickletools.py

+import pickle
 import pickletools
 from test import test_support
-test_support.run_doctest(pickletools)
+from test.pickletester import AbstractPickleTests
+from test.pickletester import AbstractPickleModuleTests
+
+class OptimizedPickleTests(AbstractPickleTests, AbstractPickleModuleTests):
+
+    def dumps(self, arg, proto=0, fast=0):
+        return pickletools.optimize(pickle.dumps(arg, proto))
+
+    def loads(self, buf):
+        return pickle.loads(buf)
+
+    module = pickle
+    error = KeyError
+
+def test_main():
+    test_support.run_unittest(OptimizedPickleTests)
+    test_support.run_doctest(pickletools)
+
+
+if __name__ == "__main__":
+    test_main()