Tests: Add Basic test for graph command

system/requirements.txt

@@ -4,3 +4,4 @@ requests-unixsocket
 python-swiftclient
 flake8
 termcolor
+pillow

system/t13_graph/__init__.py

@@ -0,0 +1,3 @@
+"""
+Testing Aptly Graph Command
+"""

system/t13_graph/graph.py

@@ -0,0 +1,25 @@
+from PIL import Image
+from lib import BaseTest
+
+
+class GraphTest1(BaseTest):
+    """
+    Test that graph is generated correctly and accessible at the specified output path.
+    """
+
+    fixtureDB = True
+    fixturePool = True
+    fixtureCmds = [
+        "aptly snapshot create snap1 from mirror gnuplot-maverick",
+        "aptly publish snapshot -skip-signing snap1",
+    ]
+    runCmd = "aptly graph -output=graph.png -layout=horizontal"
+
+    def check(self):
+        self.check_exists("graph.png")
+
+        with Image.open("graph.png") as img:
+            (width, height) = img.size
+            # check is horizontal
+            self.check_gt(width, height)
+            img.verify()