System test for aptly snapshot create empty.

system/t05_snapshot/CreateSnapshot4Test_gold

@@ -0,0 +1,3 @@
+
+Snapshot snap4 successfully created.
+You can run 'aptly publish snapshot snap4' to publish snapshot as Debian repository.

system/t05_snapshot/CreateSnapshot4Test_snapshot_show

@@ -0,0 +1,4 @@
+Name: snap4
+Description: Created as empty
+Number of packages: 0
+Packages:

system/t05_snapshot/CreateSnapshot5Test_gold

@@ -0,0 +1 @@
+ERROR: unable to add snapshot: snapshot with name snap5 already exists

system/t05_snapshot/create.py

@@ -34,3 +34,26 @@ class CreateSnapshot3Test(BaseTest):
     fixtureCmds = ["aptly snapshot create snap1 from mirror wheezy-main"]
     runCmd = "aptly snapshot create snap1 from mirror wheezy-contrib"
     expectedCode = 1
+
+
+class CreateSnapshot4Test(BaseTest):
+    """
+    create snapshot: empty
+    """
+    runCmd = "aptly snapshot create snap4 empty"
+
+    def check(self):
+        def remove_created_at(s):
+            return re.sub(r"Created At: [0-9:A-Za-z -]+\n", "", s)
+
+        self.check_output()
+        self.check_cmd_output("aptly snapshot show -with-packages snap4", "snapshot_show", match_prepare=remove_created_at)
+
+
+class CreateSnapshot5Test(BaseTest):
+    """
+    create snapshot: empty duplicate name
+    """
+    fixtureCmds = ["aptly snapshot create snap5 empty"]
+    runCmd = "aptly snapshot create snap5 empty"
+    expectedCode = 1