[gedit] build: add require_all_tests option

[Sébastien Wilmet <swilmet src gnome org>]

commit 14055fee82e5edde29e47bb574e6dc17489afa05
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon Mar 16 10:59:34 2020 +0100

    build: add require_all_tests option
    
    Currently it's applied only to the data/ directory.

 data/meson.build  |  6 +++---
 meson.build       |  1 +
 meson_options.txt | 10 ++++++++++
 3 files changed, 14 insertions(+), 3 deletions(-)
---
diff --git a/data/meson.build b/data/meson.build
index 789b41d57..92fb4cf49 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -12,7 +12,7 @@ appdata_file = i18n.merge_file(
   install_dir: join_paths(get_option('prefix'), get_option('datadir'), 'metainfo')
 )
 
-appstream_util = find_program('appstream-util', required: false)
+appstream_util = find_program('appstream-util', required: get_option('require_all_tests'))
 if appstream_util.found()
   test(
     'validate-appdata',
@@ -36,7 +36,7 @@ desktop_output_file = i18n.merge_file(
   install_dir: join_paths(get_option('prefix'), get_option('datadir'), 'applications')
 )
 
-desktop_file_validate = find_program('desktop-file-validate', required: false)
+desktop_file_validate = find_program('desktop-file-validate', required: get_option('require_all_tests'))
 if desktop_file_validate.found()
   test(
     'validate-desktop',
@@ -79,7 +79,7 @@ gschema_dtd = join_paths(
   'gschema.dtd',
 )
 
-xmllint = find_program('xmllint', required: false)
+xmllint = find_program('xmllint', required: get_option('require_all_tests'))
 if xmllint.found()
   test(
     'validate-gschema',
diff --git a/meson.build b/meson.build
index 7ca5bbae6..ace86d91d 100644
--- a/meson.build
+++ b/meson.build
@@ -114,6 +114,7 @@ summary = [
   '        Prefix:                @0@'.format(get_option('prefix')),
   '        API documentation:     @0@'.format(get_option('gtk_doc')),
   '        User documentation:    @0@'.format(get_option('user_documentation')),
+  '        Require all tests:     @0@'.format(get_option('require_all_tests')),
   '',
 ]
 message('\n'.join(summary))
diff --git a/meson_options.txt b/meson_options.txt
index 3ba395501..baaf67aa9 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -4,6 +4,16 @@ option(
   description: 'Build API reference for plugins (requires gtk-doc)'
 )
 
+# If this option is kept to false, then it's an automatic behavior: if the
+# third party program is found, then the test is defined.
+# Setting this option to true will stop the configure phase with a hard error
+# if a third party program is not found and is required to define a test.
+option(
+  'require_all_tests',
+  type: 'boolean', value: false,
+  description: 'Require that all tests can be run, even those that depend on third party programs'
+)
+
 # This option exists for the developers, to speed up the install.
 option(
   'user_documentation',