meson: add test case that verifies f00bar can be executed

meson.build

@@ -83,7 +83,7 @@ subdir('decorations')
 subdir('particles')
 subdir('modules')
 
-executable(
+f00bar = executable(
   'f00bar',
   'color.h',
   'config-verify.c', 'config-verify.h',
@@ -105,6 +105,8 @@ executable(
   install: true,
   install_rpath: '$ORIGIN/../' + get_option('libdir') + '/f00bar')
 
+test('f00bar-is-executable', f00bar, args: ['--version'])
+
 install_headers(
   'color.h',
   'config.h',