Install netcat-openbsd in tests and update screenshots for ubuntu 24.04

.github/workflows/test.yaml

@@ -66,7 +66,7 @@ jobs:
           echo "::group::Install netcat, a test dependency"
           docker exec --user root $container_id bash -c '
               apt update
-              apt install -y netcat
+              apt install -y netcat-openbsd
           '
           echo "::endgroup::"
 
@@ -95,6 +95,7 @@ jobs:
           export CONTAINER_ID=$container_id
           export JUPYTER_HOST=http://localhost:8888
           export JUPYTER_TOKEN=secret
+          export VNCSERVER=${{ matrix.vncserver }}
 
           python -mpytest -vs
 

README.md

@@ -12,6 +12,8 @@ This is based on https://github.com/ryanlovett/nbnovnc.
 
 When this extension is launched it will run a Linux desktop on the Jupyter single-user server, and proxy it to your browser using VNC via Jupyter.
 
+![Screenshot of jupyter-remote-desktop-proxy XFCE desktop](https://raw.githubusercontent.com/jupyterhub/jupyter-remote-desktop-proxy/main/tests/reference/desktop.png)
+
 ## VNC Server
 
 This extension requires a [VNC Server](https://en.wikipedia.org/wiki/Virtual_Network_Computing)

tests/test_browser.py

@@ -12,15 +12,21 @@
 CONTAINER_ID = getenv("CONTAINER_ID", "test")
 JUPYTER_HOST = getenv("JUPYTER_HOST", "http://localhost:8888")
 JUPYTER_TOKEN = getenv("JUPYTER_TOKEN", "secret")
+VNCSERVER = getenv("VNCSERVER")
 
 
-def compare_screenshot(test_image, threshold=2):
+def compare_screenshot(test_image):
     # Compare images by calculating the mean absolute difference
     # Images must be the same size
     # threshold: Average difference per pixel, this depends on the image type
     # e.g. for 24 bit images (8 bit RGB pixels) threshold=1 means a maximum
     # difference of 1 bit per pixel per channel
     reference = Image.open(HERE / "reference" / "desktop.png")
+    threshold = 2
+    if VNCSERVER == "turbovnc":
+        reference = Image.open(HERE / "reference" / "desktop-turbovnc.png")
+        # The TurboVNC screenshot varies a lot more than TigerVNC
+        threshold = 6
     test = Image.open(test_image)
 
     # Absolute difference
@@ -53,7 +59,7 @@ def test_desktop(browser):
     page1.wait_for_timeout(5000)
     # Use a non temporary folder so we can check it manually if necessary
     screenshot = Path("screenshots") / "desktop.png"
-    page1.locator("canvas").screenshot(path=screenshot)
+    page1.locator("body").screenshot(path=screenshot)
 
     # Open clipboard, enter random text, close clipboard
     clipboard_text = str(uuid4())