Tests for aptly snapshot diff.

system/t05_snapshot/DiffSnapshot1Test_gold

@@ -0,0 +1,7 @@
+  Arch   | Package                                  | Version in A                             | Version in B
++ all    | init-system-helpers                      | -                                        | 1.11~bpo70.1                            
+! amd64  | libestr0                                 | 0.1.1-2                                  | 0.1.9-1~bpo70+1                         
+! amd64  | rsyslog                                  | 5.8.11-3                                 | 7.4.4-1~bpo70+1                         
+! i386   | libestr0                                 | 0.1.1-2                                  | 0.1.9-1~bpo70+1                         
+! i386   | rsyslog                                  | 5.8.11-3                                 | 7.4.4-1~bpo70+1                         
+

system/t05_snapshot/DiffSnapshot4Test_gold

@@ -0,0 +1 @@
+ERROR: unable to load snapshot B: snapshot with name snap-no not found

system/t05_snapshot/DiffSnapshot5Test_gold

@@ -0,0 +1 @@
+ERROR: unable to load snapshot A: snapshot with name snap-no not found

system/t05_snapshot/__init__.py

@@ -7,3 +7,4 @@ from .show import *
 from .list import *
 from .verify import *
 from .pull import *
+from .diff import *

system/t05_snapshot/diff.py

@@ -0,0 +1,62 @@
+from lib import BaseTest
+
+
+class DiffSnapshot1Test(BaseTest):
+    """
+    diff two snapshots: normal diff
+    """
+    fixtureDB = True
+    fixtureCmds = [
+        "aptly snapshot create snap1 from mirror wheezy-main",
+        "aptly snapshot create snap2 from mirror wheezy-backports",
+        "aptly snapshot pull snap1 snap2 snap3 'rsyslog (>= 7.4.4)'"
+    ]
+    runCmd = "aptly snapshot diff snap1 snap3"
+
+
+class DiffSnapshot2Test(BaseTest):
+    """
+    diff two snapshots: normal diff II
+    """
+    fixtureDB = True
+    fixtureCmds = [
+        "aptly snapshot create snap1 from mirror wheezy-main",
+        "aptly snapshot create snap2 from mirror wheezy-backports",
+    ]
+    runCmd = "aptly snapshot diff snap1 snap2"
+
+
+class DiffSnapshot3Test(BaseTest):
+    """
+    diff two snapshots: normal diff II + only-matching
+    """
+    fixtureDB = True
+    fixtureCmds = [
+        "aptly snapshot create snap1 from mirror wheezy-main",
+        "aptly snapshot create snap2 from mirror wheezy-backports",
+    ]
+    runCmd = "aptly snapshot diff -only-matching snap1 snap2"
+
+
+class DiffSnapshot4Test(BaseTest):
+    """
+    diff two snapshots: doesn't exist
+    """
+    fixtureDB = True
+    fixtureCmds = [
+        "aptly snapshot create snap1 from mirror wheezy-main",
+    ]
+    runCmd = "aptly snapshot diff -only-matching snap1 snap-no"
+    expectedCode = 1
+
+
+class DiffSnapshot5Test(BaseTest):
+    """
+    diff two snapshots: doesn't exist
+    """
+    fixtureDB = True
+    fixtureCmds = [
+        "aptly snapshot create snap2 from mirror wheezy-main",
+    ]
+    runCmd = "aptly snapshot diff -only-matching snap-no snap2"
+    expectedCode = 1