diff --git a/.github/workflows/test-linux.yml b/.github/workflows/test-linux.yml
index 93e83f7..37e1999 100644
--- a/.github/workflows/test-linux.yml
+++ b/.github/workflows/test-linux.yml
@@ -26,7 +26,9 @@ on:
 jobs:
   Test:
     name: ${{ matrix.instance }}
-    runs-on: ubuntu-20.04
+    ## DGM runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
+    container: ubuntu-22.04
     timeout-minutes: ${{ inputs.timeout }}
     strategy:
       max-parallel: 2
diff --git a/tests/integration/test_installation.py b/tests/integration/test_installation.py
index 1904d04..00da095 100644
--- a/tests/integration/test_installation.py
+++ b/tests/integration/test_installation.py
@@ -27,8 +27,10 @@ def run_salt_call(cmd):
     cmd.append("--out=json")
     result = subprocess.run(cmd, capture_output=True, text=True)
     print(f"DGM run_salt_call, cmd '{cmd}', result '{result}'", flush=True)
-    json_data = json.loads(result.stdout)
-    return json_data["local"]
+    if result.stdout:
+        json_data = json.loads(result.stdout)
+        return json_data["local"]
+    return None
 
 
 def test_ping():