agl-compositor: Add test case

Include a basic test for agl-compositor which downloads the required
packages and launches the compositor.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

test-cases/agl-compositor.yaml

+metadata:
+  name: agl-compositor
+  format: "Apertis Test Definition 1.0"
+  image-types:
+    minimal:  [ armhf, amd64 ]
+  image-deployment:
+    - APT
+  type: functional
+  exec-type: manual
+  priority: high
+  maintainer: "Apertis Project"
+  description: "Test agl-compositor is able to run."
+
+  resources:
+    - "A monitor connected to the testing target."
+
+  expected:
+    - "This test show a basic desktop based on Maynard on top of agl-compositor
+       with a launcher for applications and a menu for audio volume"
+    - "@agl-compositor-screenshot.png"
+
+run:
+  steps:
+    - "HMI and Development repositores should be enabled"
+    - $ sudo apertis-dev
+    - "Install agl-compositor and maynard packages"
+    - $ sudo apt-get install agl-compositor maynard
+    - "Run agl-compositor:"
+    - $ sudo XDG_RUNTIME_DIR=/tmp agl-compositor --tty=7
+    - "Verify that a desktop shows in screen"