List snapshots by time: added integration tests

Added a couple of integration tests for the new list snapshot by
creation time feature.

system/t05_snapshot/ListSnapshot5Test_gold

@@ -0,0 +1,5 @@
+snap2
+snap1
+snap3
+snap4
+snap5

system/t05_snapshot/ListSnapshot6Test_gold

@@ -0,0 +1,8 @@
+List of snapshots:
+ * [snap2]: Snapshot from mirror [wheezy-contrib]: http://mirror.yandex.ru/debian/ wheezy
+ * [snap1]: Snapshot from mirror [wheezy-main]: http://mirror.yandex.ru/debian/ wheezy
+ * [snap3]: Merged from sources: 'snap1', 'snap2'
+ * [snap4]: Pulled into 'snap1' with 'snap2' as source, pull request was: 'mame unrar'
+ * [snap5]: Snapshot from local repo [local-repo]
+
+To get more information about snapshot, run `aptly snapshot show <name>`.

system/t05_snapshot/list.py

@@ -47,3 +47,36 @@ class ListSnapshot4Test(BaseTest):
     list snapshots: raw empty list
     """
     runCmd = "aptly snapshot -raw list"
+
+
+class ListSnapshot5Test(BaseTest):
+    """
+    list snapshots: raw regular list sorted by time
+    """
+    fixtureDB = True
+    fixtureCmds = [
+        "aptly snapshot create snap2 from mirror wheezy-main",
+        "aptly snapshot create snap1 from mirror wheezy-contrib",
+        "aptly snapshot merge snap3 snap1 snap2",
+        "aptly snapshot pull snap1 snap2 snap4 mame unrar",
+        "aptly repo create local-repo",
+        "aptly repo add local-repo ${files}",
+        "aptly snapshot create snap5 from repo local-repo",
+    ]
+    runCmd = "aptly -raw -sort=time snapshot list"
+
+class ListSnapshot6Test(BaseTest):
+    """
+    list snapshots: regular list sorted by time
+    """
+    fixtureDB = True
+    fixtureCmds = [
+        "aptly snapshot create snap2 from mirror wheezy-contrib",
+        "aptly snapshot create snap1 from mirror wheezy-main",
+        "aptly snapshot merge snap3 snap1 snap2",
+        "aptly snapshot pull snap1 snap2 snap4 mame unrar",
+        "aptly repo create local-repo",
+        "aptly repo add local-repo ${files}",
+        "aptly snapshot create snap5 from repo local-repo",
+    ]
+    runCmd = "aptly -sort=time snapshot list"