gio: tests: memory-monitor-poll: test for the poll backend of GMemoryMonitor

The unit test inplementation for GMemoryMonitor poll backend. The test includes
loading the API and the signals of LOW, MEDIUM, and CRITICAL level.

gio/tests/memory-monitor-poll.c

@@ -0,0 +1,144 @@
+/* GIO - GLib Input, Output and Streaming Library
+ *
+ * Copyright 2025 Red Hat, Inc.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "gio.h"
+
+#include "gmemorymonitorbase.h"
+#include "gmemorymonitorpoll.h"
+
+typedef struct
+{
+  double simulated_mem_free_ratio;
+  int expected_warning_level;
+} TestData;
+
+static void
+memory_monitor_signal_cb (GMemoryMonitor             *m,
+                          GMemoryMonitorWarningLevel  level,
+                          void                       *user_data)
+{
+  int *out_warning_level = user_data;
+
+  g_assert_cmpint (*out_warning_level, ==, -1);
+  *out_warning_level = level;
+
+  g_main_context_wakeup (NULL);
+}
+
+static void
+test_dup_default (void)
+{
+  GMemoryMonitor *monitor;
+
+  monitor = g_memory_monitor_dup_default ();
+  g_assert_nonnull (monitor);
+  g_object_unref (monitor);
+}
+
+static void
+test_event (const void *data)
+{
+  const TestData *test_data = data;
+  GMemoryMonitorPoll *monitor;
+  GError *local_error = NULL;
+  int warning_level = -1;
+  unsigned long warning_id;
+
+  monitor = g_object_new (G_TYPE_MEMORY_MONITOR_POLL,
+                          "poll-interval-ms", 50,
+                          "mem-free-ratio", test_data->simulated_mem_free_ratio,
+                          NULL);
+  g_initable_init (G_INITABLE (monitor), NULL, &local_error);
+  g_assert_no_error (local_error);
+
+  warning_id = g_signal_connect (monitor, "low-memory-warning",
+                                 G_CALLBACK (memory_monitor_signal_cb), &warning_level);
+
+  while (warning_level == -1)
+    g_main_context_iteration (NULL, TRUE);
+
+  g_assert_cmpint (warning_level, ==, test_data->expected_warning_level);
+
+  g_signal_handler_disconnect (monitor, warning_id);
+  g_object_unref (monitor);
+}
+
+static void
+warning_cb (GMemoryMonitor *m,
+            GMemoryMonitorWarningLevel level,
+            GMainLoop *test_loop)
+{
+  char *str = g_enum_to_string (G_TYPE_MEMORY_MONITOR_WARNING_LEVEL, level);
+  g_free (str);
+  g_main_loop_quit (test_loop);
+}
+
+static void
+do_watch_memory (void)
+{
+  GMemoryMonitor *m;
+  GMainLoop *loop;
+
+  m = g_memory_monitor_dup_default ();
+  loop = g_main_loop_new (NULL, TRUE);
+  g_signal_connect (G_OBJECT (m), "low-memory-warning",
+                    G_CALLBACK (warning_cb), loop);
+
+  g_main_loop_run (loop);
+
+  g_signal_handlers_disconnect_by_func (G_OBJECT (m),
+                                        G_CALLBACK (warning_cb), loop);
+
+  g_main_loop_unref (loop);
+  g_clear_object (&m);
+}
+
+int
+main (int argc, char **argv)
+{
+  if (argc == 2 && strcmp (argv[1], "--watch") == 0)
+    {
+      do_watch_memory ();
+      return 0;
+    }
+
+  g_setenv ("GIO_USE_MEMORY_MONITOR", "poll", TRUE);
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/memory-monitor-poll/dup-default", test_dup_default);
+
+  g_test_add_data_func ("/memory-monitor-poll/critical-event",
+                        &((const TestData) {
+                          .simulated_mem_free_ratio = 0.19,
+                          .expected_warning_level = 255,
+                        }), test_event);
+  g_test_add_data_func ("/memory-monitor-poll/medium-event",
+                        &((const TestData) {
+                          .simulated_mem_free_ratio = 0.29,
+                          .expected_warning_level = 100,
+                        }), test_event);
+  g_test_add_data_func ("/memory-monitor-poll/low-event",
+                        &((const TestData) {
+                          .simulated_mem_free_ratio = 0.39,
+                          .expected_warning_level = 50,
+                        }), test_event);
+
+  return g_test_run ();
+}

gio/tests/meson.build

@@ -155,6 +155,12 @@ gio_tests = {
   'win32-appinfo' : {},
 }
 
+if glib_conf.has('HAVE_SYSINFO')
+  gio_tests += {
+    'memory-monitor-poll' : {},
+  }
+endif
+
 if glib_have_cocoa
   gio_tests += {
     'osx-appinfo' : {}