[gtk/introspection-test] Add an introspection api test

[Matthias Clasen <matthiasc src gnome org>]

commit ba9827fd3af366d1a5a8ac840dc130a5eda064b7
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue May 4 20:39:52 2021 -0400

    Add an introspection api test
    
    Every beginning is small... just check one constant for now.

 meson.build                         |  2 ++
 testsuite/introspection/api.py      | 10 ++++++++++
 testsuite/introspection/meson.build |  8 ++++++++
 testsuite/meson.build               |  4 ++++
 4 files changed, 24 insertions(+)
---
diff --git a/meson.build b/meson.build
index d8660cbe85..6d01443291 100644
--- a/meson.build
+++ b/meson.build
@@ -732,6 +732,8 @@ int main () {
   endif
 endif
 
+project_build_root = meson.current_build_dir()
+
 subdir('gtk/css')
 subdir('gdk')
 subdir('gsk')
diff --git a/testsuite/introspection/api.py b/testsuite/introspection/api.py
new file mode 100755
index 0000000000..c35b2b7448
--- /dev/null
+++ b/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'
diff --git a/testsuite/introspection/meson.build b/testsuite/introspection/meson.build
new file mode 100644
index 0000000000..58eea5aca2
--- /dev/null
+++ b/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),
+     ])
diff --git a/testsuite/meson.build b/testsuite/meson.build
index fafe6ea140..0b75c90811 100644
--- a/testsuite/meson.build
+++ b/testsuite/meson.build
@@ -56,3 +56,7 @@ subdir('css')
 subdir('a11y')
 subdir('tools')
 subdir('reftests')
+
+if build_gir
+  subdir('introspection')
+endif