Make bootstrap test name / description more generic

integration-tests/test_bootstrap.py

@@ -0,0 +1,44 @@
+"""
+Test running bootstrap script in different circumstances
+"""
+import subprocess
+
+
+def test_ubuntu_too_old():
+    """
+    Error with a useful message when running in older Ubuntu
+    """
+    container_name = 'old-distro-test'
+
+    # stop container if it is already running
+    subprocess.run([
+        'docker', 'rm', '-f', container_name
+    ])
+    
+    # Start a detached Ubuntu 16.04 container
+    subprocess.check_call([
+        'docker', 'run', '--detach', '--name', container_name, 'ubuntu:16.04', 
+        '/bin/bash', '-c', 'sleep 1000s'
+    ])
+    # Install python3 inside the ubuntu container
+    # There is no trusted Ubuntu+Python3 container we can use
+    subprocess.check_output([
+        'docker', 'exec', container_name, 'apt-get', 'update'
+    ])
+    subprocess.check_output([
+        'docker', 'exec', container_name, 'apt-get', 'install', '--yes', 'python3'
+    ])
+    # Copy only the bootstrap script  to container, so this is faster
+    subprocess.check_call([
+        'docker',
+        'cp',
+        'bootstrap/', f'{container_name}:/srv'
+    ])
+
+    # Run bootstrap script, validate that it fails appropriately
+    output = subprocess.run([
+        'docker', 'exec', '-i', container_name,
+        'python3', '/srv/bootstrap/bootstrap.py'
+    ], check=False, stdout=subprocess.PIPE, encoding='utf-8')
+    assert output.stdout == 'The Littlest JupyterHub requires Ubuntu 18.04 or higher\n'
+    assert output.returncode == 1