diff --git a/gio/tests/filenamecompleter.c b/gio/tests/filenamecompleter.c
new file mode 100644
index 000000000..5849fc5c7
--- /dev/null
+++ b/gio/tests/filenamecompleter.c
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2025 Khalid Abu Shawarib.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * Author: Khalid Abu Shawarib <kas@gnome.org>
+ */
+
+#include <gio/gio.h>
+
+static void
+create_files (const GStrv hier)
+{
+  g_mkdir_with_parents (g_get_home_dir (), 0700);
+
+  for (guint i = 0; hier[i] != NULL; i++)
+    {
+      GFile *file = g_file_new_build_filename (g_get_home_dir (), hier[i], NULL);
+      gboolean is_directory = g_str_has_suffix (hier[i], G_DIR_SEPARATOR_S);
+
+      if (is_directory)
+        g_file_make_directory (file, NULL, NULL);
+      else
+        {
+          GFileOutputStream *stream = g_file_create (file, G_FILE_CREATE_NONE, NULL, NULL);
+
+          g_object_unref (stream);
+        }
+
+      g_assert_true (g_file_query_exists (file, NULL));
+
+      g_object_unref (file);
+    }
+}
+
+static GStrv
+prefix_filenames (const gchar *const strings[],
+                  const gchar *prefix)
+{
+  GStrvBuilder *builder = g_strv_builder_new ();
+
+  for (guint i = 0; strings[i] != NULL; i++)
+    g_strv_builder_take (builder, g_build_filename (prefix, strings[i], NULL));
+
+  return g_strv_builder_unref_to_strv (builder);
+}
+
+typedef struct
+{
+  const gchar *string;
+  const gchar *all_completion_suffix;
+  const gchar *dirs_completion_suffix;
+  const gchar *const all_completions[5];
+  const gchar *const dirs_completions[5];
+} FilenameCompleterTestCase;
+
+static void
+run_test_cases (const FilenameCompleterTestCase test_cases[],
+                guint len)
+{
+  const gchar *base_path = g_get_home_dir ();
+
+  for (guint i = 0; i < len; i++)
+    {
+      GFilenameCompleter *all_completer = g_filename_completer_new ();
+      GFilenameCompleter *dirs_completer = g_filename_completer_new ();
+      gchar *completion_suffix;
+      GStrv all_results_completions, all_expected_completions;
+      GStrv dirs_results_completions, dirs_expected_completions;
+      gchar *path_to_complete = g_build_filename (base_path, test_cases[i].string, NULL);
+      GMainLoop *loop = g_main_loop_new (NULL, FALSE);
+
+      /* dirs_only = FALSE */
+      g_signal_connect_swapped (all_completer, "got-completion-data",
+                                G_CALLBACK (g_main_loop_quit), loop);
+      g_filename_completer_set_dirs_only (all_completer, FALSE);
+      g_strfreev (g_filename_completer_get_completions (all_completer, path_to_complete));
+
+      g_main_loop_run (loop);
+
+      all_expected_completions = prefix_filenames (test_cases[i].all_completions, base_path);
+      all_results_completions = g_filename_completer_get_completions (all_completer, path_to_complete);
+      g_assert_cmpstrv (all_expected_completions, all_results_completions);
+      g_strfreev (all_expected_completions);
+      g_strfreev (all_results_completions);
+
+      completion_suffix = g_filename_completer_get_completion_suffix (all_completer,
+                                                                      path_to_complete);
+      g_assert_cmpstr (test_cases[i].all_completion_suffix, ==, completion_suffix);
+      g_free (completion_suffix);
+
+      /* dirs_only = TRUE */
+      g_signal_connect_swapped (dirs_completer, "got-completion-data",
+                                G_CALLBACK (g_main_loop_quit), loop);
+      g_filename_completer_set_dirs_only (dirs_completer, TRUE);
+      g_strfreev (g_filename_completer_get_completions (dirs_completer, path_to_complete));
+
+      g_main_loop_run (loop);
+
+      dirs_expected_completions = prefix_filenames (test_cases[i].dirs_completions, base_path);
+      dirs_results_completions = g_filename_completer_get_completions (dirs_completer, path_to_complete);
+      g_assert_cmpstrv (dirs_expected_completions, dirs_results_completions);
+
+      g_strfreev (dirs_expected_completions);
+      g_strfreev (dirs_results_completions);
+
+      completion_suffix = g_filename_completer_get_completion_suffix (dirs_completer,
+                                                                      path_to_complete);
+      g_assert_cmpstr (test_cases[i].dirs_completion_suffix, ==, completion_suffix);
+      g_free (completion_suffix);
+
+      g_object_unref (all_completer);
+      g_object_unref (dirs_completer);
+      g_free (path_to_complete);
+      g_main_loop_unref (loop);
+    }
+}
+
+static void
+test_completions (void)
+{
+  const GStrv files_hier = (char *[]){
+    "file_1",
+    "file_2",
+    "folder_1" G_DIR_SEPARATOR_S,
+    "folder_2" G_DIR_SEPARATOR_S,
+    NULL
+  };
+  const FilenameCompleterTestCase test_cases[] = {
+    {
+        "f",
+        "",
+        "older_",
+        { "file_1",
+          "file_2",
+          "folder_1" G_DIR_SEPARATOR_S,
+          "folder_2" G_DIR_SEPARATOR_S,
+          NULL },
+        { "folder_1" G_DIR_SEPARATOR_S,
+          "folder_2" G_DIR_SEPARATOR_S,
+          NULL },
+    },
+
+    {
+        "fi",
+        "le_",
+        NULL,
+        { "file_1",
+          "file_2",
+          NULL },
+        { NULL },
+    },
+
+    {
+        "fo",
+        "lder_",
+        "lder_",
+        { "folder_1" G_DIR_SEPARATOR_S,
+          "folder_2" G_DIR_SEPARATOR_S,
+          NULL },
+        { "folder_1" G_DIR_SEPARATOR_S,
+          "folder_2" G_DIR_SEPARATOR_S,
+          NULL },
+    },
+  };
+
+  create_files (files_hier);
+
+  run_test_cases (test_cases, G_N_ELEMENTS (test_cases));
+}
+
+int
+main (int argc, char *argv[])
+{
+  g_setenv ("LC_ALL", "C", TRUE);
+
+  g_test_init (&argc, &argv, G_TEST_OPTION_ISOLATE_DIRS, NULL);
+
+  g_test_add_func ("/filenamecompleter/basic", test_completions);
+
+  return g_test_run ();
+}
diff --git a/gio/tests/meson.build b/gio/tests/meson.build
index ced8abb72..32ebda362 100644
--- a/gio/tests/meson.build
+++ b/gio/tests/meson.build
@@ -74,6 +74,7 @@ gio_tests = {
   'error': {},
   'file-thumbnail' : {},
   'fileattributematcher' : {},
+  'filenamecompleter' : {},
   'filter-streams' : {},
   'giomodule' : {
     'depends' : glib_build_shared ? [libtestmodulea, libtestmoduleb] : [],