Added tests of running DemoStorage under ZEO. Sadly, this doesn't

detect the fact that DemoStorage doesn't implement getTid and that
theerfore cache verification is broken.  This still needs to be
pursued.

src/ZEO/tests/testZEO.py

@@ -222,6 +222,36 @@ class MappingStorageTests(GenericTests):
     def getConfig(self):
         return """<mappingstorage 1/>"""
 
+class DemoStorageTests(
+    GenericTests,
+    Cache.StorageWithCache,
+    VersionStorage.VersionStorage,
+    ):
+
+    def getConfig(self):
+        return """
+        <demostorage 1>
+          <filestorage 1>
+             path %s
+          </filestorage>
+        </demostorage>
+        """ % tempfile.mktemp()
+
+    def checkLoadBeforeVersion(self):
+        # Doesn't implement loadBefore, except as a kind of place holder.
+        pass
+    
+    # the next three pack tests depend on undo
+
+    def checkPackVersionReachable(self):
+        pass
+
+    def checkPackVersions(self):
+        pass
+
+    def checkPackVersionsInPast(self):
+        pass
+
 class HeartbeatTests(ZEO.tests.ConnectionTests.CommonSetupTearDown):
     """Make sure a heartbeat is being sent and that it does no harm
 
@@ -782,7 +812,7 @@ transaction, we'll get a result:
     """
 
 
-test_classes = [FileStorageTests, MappingStorageTests,
+test_classes = [FileStorageTests, MappingStorageTests, DemoStorageTests,
                 BlobAdaptedFileStorageTests, BlobWritableCacheTests]