[gnome-software] shell-extensions: Don't run tests if no user shell extensions installed

[Richard Hughes <rhughes src gnome org>]

commit e9b11751816183067a8b85c9647ab39e65e5d159
Author: Robert Ancell <robert ancell canonical com>
Date:   Mon Jul 15 11:15:04 2019 +1200

    shell-extensions: Don't run tests if no user shell extensions installed
    
    The tests check the user extensions in the running shell. This won't work if
    there aren't any installed.
    
    Fixes #728

 plugins/shell-extensions/gs-self-test.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/plugins/shell-extensions/gs-self-test.c b/plugins/shell-extensions/gs-self-test.c
index 45695b78..f96ee60d 100644
--- a/plugins/shell-extensions/gs-self-test.c
+++ b/plugins/shell-extensions/gs-self-test.c
@@ -36,7 +36,12 @@ gs_plugins_shell_extensions_installed_func (GsPluginLoader *plugin_loader)
        gs_test_flush_main_context ();
        g_assert_no_error (error);
        g_assert (list != NULL);
-       g_assert_cmpint (gs_app_list_length (list), >, 1);
+
+       /* no shell-extensions installed, abort */
+       if (gs_app_list_length (list) < 1) {
+               g_test_skip ("no shell extensions installed");
+               return;
+       }
 
        /* test properties */
        app = gs_app_list_lookup (list, "*/*/*/*/background-logo_fedorahosted.org/*");