enable writing of only selected output paths

- add WRITE_SELECTED setting
- add --write-selected commandline option

pelican/tests/test_pelican.py

@@ -138,3 +138,26 @@ class TestPelican(LoggedTestCase):
 
         for file in ['a_stylesheet', 'a_template']:
             self.assertTrue(os.path.exists(os.path.join(theme_output, file)))
+
+    def test_write_only_selected(self):
+        """Test that only the selected files are written"""
+        settings = read_settings(path=None, override={
+            'PATH': INPUT_PATH,
+            'OUTPUT_PATH': self.temp_path,
+            'CACHE_DIRECTORY': self.temp_cache,
+            'WRITE_SELECTED': [
+                os.path.join(self.temp_path, 'oh-yeah.html'),
+                os.path.join(self.temp_path, 'categories.html'),
+                ],
+            'LOCALE': locale.normalize('en_US'),
+            })
+        pelican = Pelican(settings=settings)
+        logger = logging.getLogger()
+        orig_level = logger.getEffectiveLevel()
+        logger.setLevel(logging.INFO)
+        mute(True)(pelican.run)()
+        logger.setLevel(orig_level)
+        self.assertLogCountEqual(
+            count=2,
+            msg="writing .*",
+            level=logging.INFO)