Merge branch 'fix/update-check-reports-failure' of https://github.com/ChuckBuilds/LEDMatrix into consolidate/web

test/test_update_check_reports_failure.py

@@ -0,0 +1,85 @@
+"""A check that could not run must not be reported as "up to date".
+
+check-update returned update_available=False whenever git failed. The banner
+is the only route to the update button, so a checkout git refuses to touch
+looked exactly like a current one -- permanently, and with nothing for the
+user to act on. The usual cause is an install performed as root, after which
+every git command fails with "detected dubious ownership".
+"""
+import subprocess
+import sys
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+from flask import Flask
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from web_interface.blueprints import api_v3 as mod  # noqa: E402
+from web_interface.blueprints.api_v3 import api_v3  # noqa: E402
+
+DUBIOUS = ("fatal: detected dubious ownership in repository at "
+           "'/home/pi/LEDMatrix'\nTo add an exception for this directory, call:\n"
+           "\tgit config --global --add safe.directory /home/pi/LEDMatrix\n")
+
+
+@pytest.fixture
+def client():
+    app = Flask(__name__)
+    app.config['TESTING'] = True
+    app.register_blueprint(api_v3, url_prefix='/api/v3')
+    mod._update_check_cache['result'] = None
+    mod._update_check_cache['ts'] = 0
+    return app.test_client()
+
+
+def _fetch_fails(stderr: bytes):
+    def fake_run(args, **kwargs):
+        if args[:2] == ['git', 'fetch']:
+            return subprocess.CompletedProcess(args, 1, stdout=b'', stderr=stderr)
+        return subprocess.CompletedProcess(args, 0, stdout='', stderr='')
+    return fake_run
+
+
+class TestFailedCheckIsNotSilence:
+    def test_dubious_ownership_is_reported_not_swallowed(self, client):
+        with patch.object(mod.subprocess, 'run', _fetch_fails(DUBIOUS.encode())):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert data['check_failed'] is True, (
+            "a git failure was reported as a successful 'no update' check")
+        assert data['update_available'] is False
+
+    def test_the_message_tells_the_user_what_to_do(self, client):
+        with patch.object(mod.subprocess, 'run', _fetch_fails(DUBIOUS.encode())):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert 'chown' in data['error'], (
+            "dubious ownership is unactionable without the fix command")
+        assert 'root' in data['error']
+
+    def test_an_ordinary_git_failure_still_surfaces(self, client):
+        with patch.object(mod.subprocess, 'run',
+                          _fetch_fails(b'fatal: some other git problem\n')):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert data['check_failed'] is True
+        assert 'some other git problem' in data['error']
+
+    def test_offline_reads_as_offline(self, client):
+        with patch.object(mod.subprocess, 'run',
+                          _fetch_fails(b'fatal: could not resolve host: github.com\n')):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert 'Could not reach GitHub' in data['error']
+
+
+class TestSuccessPathUnchanged:
+    def test_up_to_date_carries_no_failure_flag(self, client):
+        def fake_run(args, **kwargs):
+            if args[:2] == ['git', 'fetch']:
+                return subprocess.CompletedProcess(args, 0, stdout=b'', stderr=b'')
+            if args[:2] == ['git', 'rev-parse']:
+                return subprocess.CompletedProcess(args, 0, stdout='abc123\n', stderr='')
+            return subprocess.CompletedProcess(args, 0, stdout='0\n', stderr='')
+        with patch.object(mod.subprocess, 'run', fake_run):
+            data = client.get('/api/v3/system/check-update').get_json()
+        assert data['update_available'] is False
+        assert not data.get('check_failed'), "a healthy check must not look like a failure"