diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1133342049..a44b2b6fb4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -344,6 +344,11 @@ jobs:
             exit $rc
           fi
 
+      - name: Testing launching GUI test
+        working-directory: tests
+        run: |
+          WX_TEST_DISABLE_GUI=1 ./test_gui
+
       - name: Testing GUI using Xvfb
         if: matrix.use_xvfb
         working-directory: tests
diff --git a/src/gtk/settings.cpp b/src/gtk/settings.cpp
index 1202e06fb0..d9245f9df5 100644
--- a/src/gtk/settings.cpp
+++ b/src/gtk/settings.cpp
@@ -186,16 +186,24 @@ static void notify_gtk_font_name(GObject*, GParamSpec*, void*)
 
 static bool UpdatePreferDark(GVariant* value)
 {
+    GtkSettings* const settings = gtk_settings_get_default();
+    // This shouldn't happen, but don't bother doing anything else if it does.
+    if (!settings)
+        return false;
+
     // 0: No preference, 1: Prefer dark appearance, 2: Prefer light appearance
     gboolean preferDark = g_variant_get_uint32(value) == 1;
 
-    GtkSettings* settings = gtk_settings_get_default();
-    char* themeName;
-    gboolean preferDarkPrev;
+    char* themeName = nullptr;
+    gboolean preferDarkPrev = false;
     g_object_get(settings,
         "gtk-theme-name", &themeName,
         "gtk-application-prefer-dark-theme", &preferDarkPrev, nullptr);
 
+    // This is not supposed to happen neither, but don't crash if it does.
+    if (!themeName)
+        return false;
+
     // We don't need to enable prefer-dark if the theme is already dark
     if (strstr(themeName, "-dark") || strstr(themeName, "-Dark"))
         preferDark = false;
diff --git a/src/x11/window.cpp b/src/x11/window.cpp
index 9b83f20900..14a8de5b9c 100644
--- a/src/x11/window.cpp
+++ b/src/x11/window.cpp
@@ -1767,6 +1767,6 @@ bool wxWinModule::OnInit()
 
 void wxWinModule::OnExit()
 {
-    Display *xdisplay = wxGlobalDisplay();
-    XFreeGC( xdisplay, g_eraseGC );
+    if (Display *xdisplay = wxGlobalDisplay())
+        XFreeGC( xdisplay, g_eraseGC );
 }
diff --git a/tests/test.cpp b/tests/test.cpp
index 5e004fb04f..e07c7118b4 100644
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -340,6 +340,9 @@ public:
 
     virtual int OnRun() override
     {
+        if ( !IsGUIEnabled() )
+            return 0;
+
         if ( TestAppBase::OnRun() != 0 )
             m_exitcode = EXIT_FAILURE;
 
@@ -352,6 +355,35 @@ public:
     }
 #endif // wxUSE_GUI/!wxUSE_GUI
 
+    // Hack to test that GUI applications not using GUI at all work: this was
+    // broken in the past (see #23981), so now the test suite checks that
+    // running this test with WX_TEST_DISABLE_GUI works.
+#if wxUSE_GUI
+    bool IsGUIEnabled() const
+    {
+        return !wxGetEnv(wxASCII_STR("WX_TEST_DISABLE_GUI"), nullptr);
+    }
+
+    virtual bool Initialize(int& argc, wxChar **argv) override
+    {
+        return IsGUIEnabled() ? wxApp::Initialize(argc, argv)
+                              : wxAppConsole::Initialize(argc, argv);
+    }
+
+    virtual bool OnInitGui() override
+    {
+        return !IsGUIEnabled() || wxApp::OnInitGui();
+    }
+
+    virtual void CleanUp() override
+    {
+        if ( IsGUIEnabled() )
+            wxApp::CleanUp();
+        else
+            wxAppConsole::CleanUp();
+    }
+#endif // wxUSE_GUI
+
 private:
     int RunTests();
 
@@ -592,6 +624,14 @@ TestApp::TestApp()
 //
 bool TestApp::OnInit()
 {
+#if wxUSE_GUI
+    if ( !IsGUIEnabled() )
+    {
+        wxFputs(wxASCII_STR("Not running tests because GUI is disabled.\n"), stderr);
+        return true;
+    }
+#endif // wxUSE_GUI
+
     // Hack: don't call TestAppBase::OnInit() to let CATCH handle command line.
 
     // Output some important information about the test environment.
@@ -688,6 +728,9 @@ int TestApp::RunTests()
 int TestApp::OnExit()
 {
 #if wxUSE_GUI
+    if ( !IsGUIEnabled() )
+        return wxAppConsole::OnExit();
+
     delete GetTopWindow();
 #endif // wxUSE_GUI