Add an introspection api test

Every beginning is small... just check one constant for now.

meson.build

@@ -733,6 +733,8 @@ int main () {
   endif
 endif
 
+project_build_root = meson.current_build_dir()
+
 subdir('gtk/css')
 subdir('gdk')
 subdir('gsk')

testsuite/introspection/api.py

@@ -0,0 +1,10 @@
+#! /usr/bin/env python3
+
+import sys
+import gi
+
+gi.require_version('Gtk', '4.0')
+
+from gi.repository import Gtk
+
+assert isinstance(Gtk.INVALID_LIST_POSITION, int), 'Gtk.INVALID_LIST_POSITION is not an int'

testsuite/introspection/meson.build

@@ -0,0 +1,8 @@
+
+test('api',
+     find_program('api.py', dirs: meson.current_source_dir()),
+     suite: ['introspection'],
+     env: [
+       'GI_TYPELIB_PATH=@0@/gtk:/usr/lib64/girepository-1.0'.format(project_build_root),
+       'LD_PRELOAD=@0@/gtk/libgtk-4.so'.format(project_build_root),
+     ])

testsuite/meson.build

@@ -56,3 +56,7 @@ subdir('css')
 subdir('a11y')
 subdir('tools')
 subdir('reftests')
+
+if build_gir
+  subdir('introspection')
+endif