[gtk/matthiasc/css-change-tracking-4: 10/20] style tests: Show the window

[Matthias Clasen <matthiasc src gnome org>]

commit c5b7f4c8be690eb4407e60418c2e557f5ace8acc
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jan 15 02:00:09 2020 -0500

    style tests: Show the window
    
    Not doing so somewhat defeats the point that we want
    to verify the regular styles, not some weird initial
    conditions.

 testsuite/css/style/test-css-style.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)
---
diff --git a/testsuite/css/style/test-css-style.c b/testsuite/css/style/test-css-style.c
index c7c0bca3aa..833cc3dc0d 100644
--- a/testsuite/css/style/test-css-style.c
+++ b/testsuite/css/style/test-css-style.c
@@ -98,12 +98,23 @@ done:
   return diff;
 }
 
+static void
+style_context_changed (GtkWidget *window, const char **output)
+{
+  GtkStyleContext *context;
+
+  context = gtk_widget_get_style_context (window);
+
+  *output = gtk_style_context_to_string (context, GTK_STYLE_CONTEXT_PRINT_RECURSE |
+                                                  GTK_STYLE_CONTEXT_PRINT_SHOW_STYLE);
+  g_main_context_wakeup (NULL);
+}
+
 static void
 load_ui_file (GFile *file, gboolean generate)
 {
   GtkBuilder *builder;
   GtkWidget *window;
-  GtkStyleContext *context;
   char *output, *diff;
   char *ui_file, *css_file, *reference_file;
   GtkCssProvider *provider;
@@ -125,10 +136,13 @@ load_ui_file (GFile *file, gboolean generate)
 
   g_assert (window != NULL);
 
-  context = gtk_widget_get_style_context (window);
+  output = NULL;
+  g_signal_connect (window, "map", G_CALLBACK (style_context_changed), &output);
+
+  gtk_widget_show (window);
 
-  output = gtk_style_context_to_string (context, GTK_STYLE_CONTEXT_PRINT_RECURSE |
-                                                 GTK_STYLE_CONTEXT_PRINT_SHOW_STYLE);
+  while (!output)
+    g_main_context_iteration (NULL, FALSE);
 
   if (generate)
     {