test: Add tests for action utilities

Signed-off-by: Fioddor Superconcentrado <fioddor@gmail.com>
[sunil: Minor refactoring, relax a test to make it work on CI]
[sunil: Run tests only when systemd, ip commands are available]
Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/tests/test_action_utils.py

@@ -0,0 +1,139 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Test module for key/value store.
+"""
+
+import json
+import pathlib
+import subprocess
+from unittest.mock import patch
+
+import pytest
+
+from plinth.action_utils import (get_addresses, get_hostname,
+                                 is_systemd_running, service_action,
+                                 service_disable, service_enable,
+                                 service_is_enabled, service_is_running,
+                                 service_reload, service_restart,
+                                 service_start, service_stop,
+                                 service_try_restart, service_unmask)
+
+UNKNOWN = 'unknowndeamon'
+
+systemctl_path = pathlib.Path('/usr/bin/systemctl')
+systemd_installed = pytest.mark.skipif(not systemctl_path.exists(),
+                                       reason='systemd not available')
+
+ip_path = pathlib.Path('/usr/bin/ip')
+ip_installed = pytest.mark.skipif(not ip_path.exists(),
+                                  reason='ip command not available')
+
+
+@patch('os.path.exists')
+def test_is_systemd_running(mock):
+    """Trivial white box test for a trivial implementation."""
+    mock.return_value = True
+    assert is_systemd_running()
+    mock.return_value = False
+    assert not is_systemd_running()
+
+
+@systemd_installed
+def test_service_checks():
+    """Test basic checks on status of an arbitrary service."""
+    assert not service_is_running(UNKNOWN)
+    assert not service_is_enabled(UNKNOWN)
+
+    # expected is best if: generic. Alternatives: systemd-sysctl, logrotate
+    expected = 'networking'
+    if not service_is_running(expected):
+        pytest.skip(f'Needs service {expected} running.')
+
+    assert service_is_enabled(expected)
+
+
+@pytest.mark.usefixtures('needs_root')
+@systemd_installed
+def test_service_enable_and_disable():
+    """Test enabling and disabling of an arbitrary service."""
+    # service is best if: non-essential part of FreedomBox that restarts fast
+    service = 'unattended-upgrades'
+    if not service_is_enabled(service):
+        reason = f'Needs service {service} enabled.'
+        pytest.skip(reason)
+
+    service_disable(service)
+    assert not service_is_running(service)
+    service_enable(service)
+    assert service_is_running(service)
+
+    # Ignore unknown services, don't fail:
+    service_disable(UNKNOWN)
+    service_enable(UNKNOWN)
+
+
+@patch('plinth.action_utils.service_action')
+@systemd_installed
+def test_service_actions(mock):
+    """Trivial white box test for trivial implementations."""
+    service_start(UNKNOWN)
+    mock.assert_called_with(UNKNOWN, 'start')
+    service_stop(UNKNOWN)
+    mock.assert_called_with(UNKNOWN, 'stop')
+    service_restart(UNKNOWN)
+    mock.assert_called_with(UNKNOWN, 'restart')
+    service_try_restart(UNKNOWN)
+    mock.assert_called_with(UNKNOWN, 'try-restart')
+    service_reload(UNKNOWN)
+    mock.assert_called_with(UNKNOWN, 'reload')
+
+
+@pytest.mark.usefixtures('needs_root')
+@systemd_installed
+def test_service_unmask():
+    """Test unmasking of an arbitrary masked service."""
+
+    def is_masked(service):
+        process = subprocess.run([
+            'systemctl', 'list-unit-files', '--output=json',
+            service + '.service'
+        ], stdout=subprocess.PIPE, check=False)
+        output = json.loads(process.stdout)
+        return output[0]['state'] == 'masked' if output else False
+
+    # SERVICE is best if: part of FreedomBox, so we can mess with least risk.
+    service = 'samba-ad-dc'
+    if not is_masked(service):
+        pytest.skip(f'Needs service {service} masked.')
+
+    service_unmask(service)
+    assert not is_masked(service)
+
+    service_action(service, 'mask')
+    assert is_masked(service)
+
+
+def test_get_hostname():
+    """get_hostname returns a string.
+
+    In fact, the maximum length for a hostname is 253 characters, but
+    anything longer than 80 is very suspicious, so we fail the test.
+
+    To avoid error messages pass as hostnames we seek and fail if we find
+    some unexpected characters.
+    """
+    hostname = get_hostname()
+    assert hostname
+    assert isinstance(hostname, str)
+    assert len(hostname) < 80
+    for char in ' ,:;!?=$%&@*+()[]{}<>"\'':
+        assert char not in hostname
+
+
+@ip_installed
+def test_get_addresses():
+    """Test that any FreedomBox has some addresses."""
+    ips = get_addresses()
+    assert len(ips) > 3  # min: ip, 2x'localhost', hostname
+    for address in ips:
+        assert address['kind'] in ('4', '6')