tests: mock user euid to be able to run tests as root

When running test as root, there is an additional log done to warn the
user that it is running streamlink as root. This causes some logging
tests to fail.

For these logging test, ensure we run with a mocked user euid when not
testing for the root euid.

src/streamlink_cli/main.py

@@ -893,7 +893,7 @@ def setup_plugin_options(session: Streamlink, plugin: Type[Plugin]):
 
 
 def log_root_warning():
-    if hasattr(os, "getuid"):
+    if hasattr(os, "geteuid"):  # pragma: no branch
         if os.geteuid() == 0:
             log.info("streamlink is running as root! Be careful!")
 

tests/test_cli_main.py

@@ -572,7 +572,8 @@ def subject(cls, argv, **kwargs):
         class StopTest(Exception):
             pass
 
-        with patch("streamlink_cli.main.streamlink", session), \
+        with patch("streamlink_cli.main.os.geteuid", create=True, new=Mock(return_value=kwargs.get("euid", 1000))), \
+             patch("streamlink_cli.main.streamlink", session), \
              patch("streamlink_cli.main.setup_signals", side_effect=StopTest), \
              patch("streamlink_cli.main.CONFIG_FILES", []), \
              patch("streamlink_cli.main.setup_streamlink"), \
@@ -694,9 +695,8 @@ def test_pipe_json(self, mock_stdout: Mock, mock_stderr: Mock):
 class TestCLIMainLoggingInfos(_TestCLIMainLogging):
     @unittest.skipIf(is_win32, "test only applicable on a POSIX OS")
     @patch("streamlink_cli.main.log")
-    @patch("streamlink_cli.main.os.geteuid", Mock(return_value=0))
     def test_log_root_warning(self, mock_log):
-        self.subject(["streamlink"])
+        self.subject(["streamlink"], euid=0)
         self.assertEqual(mock_log.info.mock_calls, [call("streamlink is running as root! Be careful!")])
 
     @patch("streamlink_cli.main.log")
@@ -902,7 +902,8 @@ def subject(self):
              patch.object(Streamlink, "resolve_url_no_redirect") as mock_resolve_url_no_redirect:
             session = Streamlink()
             session.load_plugins(os.path.join(os.path.dirname(__file__), "plugin"))
-            with patch("streamlink_cli.main.streamlink", session), \
+            with patch("streamlink_cli.main.os.geteuid", create=True, new=Mock(return_value=1000)), \
+                 patch("streamlink_cli.main.streamlink", session), \
                  patch("streamlink_cli.main.CONFIG_FILES", []), \
                  patch("streamlink_cli.main.setup_streamlink"), \
                  patch("streamlink_cli.main.setup_plugins"), \