glib/tests: Add test to check that we abort on low-memory

In case we're out of memory we should abort after having printed an error
message, this is similar to crashing but not exactly the same, so ensure
we exit for SIGABRT and not because of a SIGSEV.

We use a test wrapper to ensure that both the exit code and the stderr
match what we expected.

glib/tests/messages-low-memory.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright © 2022 Emmanuel Fleury <emmanuel.fleury@gmail.com>
+# Copyright © 2022 Marco Trevisan <mail@3v1n0.net>
+#
+# 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, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+# MA  02110-1301  USA
+
+""" Integration tests for g_message functions on low-memory. """
+
+import collections
+import os
+import subprocess
+import unittest
+
+import taptestrunner
+
+Result = collections.namedtuple("Result", ("info", "out", "err"))
+
+
+class TestMessagesLowMemory(unittest.TestCase):
+    """Integration test for checking g_message()’s behavior on low memory.
+
+    This can be run when installed or uninstalled. When uninstalled,
+    it requires G_TEST_BUILDDIR and G_TEST_SRCDIR to be set.
+
+    The idea with this test harness is to test if g_message and friends
+    assert instead of crashing if memory is exhausted, printing the expected
+    error message.
+    """
+
+    test_binary = "messages-low-memory"
+
+    def setUp(self):
+        ext = ""
+        if os.name == "nt":
+            ext = ".exe"
+        if "G_TEST_BUILDDIR" in os.environ:
+            self._test_binary = os.path.join(
+                os.environ["G_TEST_BUILDDIR"], self.test_binary + ext
+            )
+        else:
+            self._test_binary = os.path.join(
+                os.path.dirname(__file__), self.test_binary + ext
+            )
+        print("messages-low-memory:", self._test_binary)
+
+    def runTestBinary(self, *args):
+        print("Running:", *args)
+
+        env = os.environ.copy()
+        env["LC_ALL"] = "C.UTF-8"
+        print("Environment:", env)
+
+        # We want to ensure consistent line endings...
+        info = subprocess.run(
+            *args,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            env=env,
+            universal_newlines=True,
+        )
+        out = info.stdout.strip()
+        err = info.stderr.strip()
+
+        result = Result(info, out, err)
+
+        print("Return code:", result.info.returncode)
+        print("Output:", result.out)
+        print("Error:", result.err)
+        return result
+
+    def test_message_memory_allocation_failure(self):
+        """Test running g_message() when memory is exhausted."""
+        result = self.runTestBinary(self._test_binary)
+
+        if result.info.returncode == 77:
+            self.skipTest("Not supported")
+
+        if os.name == "nt":
+            self.assertEqual(result.info.returncode, 3)
+        else:
+            self.assertEqual(result.info.returncode, -6)
+        self.assertIn("failed to allocate memory", result.err)
+
+
+if __name__ == "__main__":
+    unittest.main(testRunner=taptestrunner.TAPTestRunner())