desktop: Port test-appdata.sh to Python

This works on Windows too so let's make it cross platform.

desktop/meson.build

@@ -46,7 +46,7 @@ endif
 
 if appstreamcli.found()
   test('appdata_file',
-    find_program('test-appdata.sh', required: true, dirs: [meson.current_source_dir()]),
+    find_program('test-appdata.py', required: true, dirs: [meson.current_source_dir()]),
     env: [
       'GIMP_TESTING_BUILDDIR=' + meson.current_build_dir(),
       'GIMP_RELEASE=' + (release and not gimp_rc_git ? '1' : '0'),

desktop/test-appdata.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+import os
+import sys
+import subprocess
+import tempfile
+from datetime import date
+
+os.chdir(os.environ['GIMP_TESTING_BUILDDIR'])
+if int(os.environ.get('GIMP_RELEASE', '0')) == 1:
+  result = subprocess.run(['appstreamcli', 'validate', 'org.gimp.GIMP.appdata.xml'])
+  sys.exit(result.returncode)
+else:
+  temp_fd, APPDATA = tempfile.mkstemp(prefix='org.gimp.GIMP.appdata.',suffix='.xml',dir='.')
+  with open('org.gimp.GIMP.appdata.xml', 'r', encoding='utf-8') as f:
+    content = f.read()
+  new_content = content.replace(
+    'date="TODO"',
+    f'date="{date.today().isoformat()}"'
+  )
+  with os.fdopen(temp_fd, 'w', encoding='utf-8') as f:
+    f.write(new_content)
+  result = subprocess.run(['appstreamcli', 'validate', APPDATA])
+  os.remove(APPDATA)
+  sys.exit(result.returncode)

desktop/test-appdata.sh

@@ -1,14 +0,0 @@
-#!/bin/sh
-
-cd $GIMP_TESTING_BUILDDIR
-if [ $GIMP_RELEASE -eq 1 ]; then
-  appstreamcli validate org.gimp.GIMP.appdata.xml
-  exit $?
-else
-  APPDATA=`mktemp org.gimp.GIMP.appdata.XXX.xml`
-  sed "s/date=\"TODO\"/date=\"`date --iso-8601`\"/" org.gimp.GIMP.appdata.xml > $APPDATA
-  appstreamcli validate $APPDATA
-  success=$?
-  rm $APPDATA
-  exit $success
-fi