Don't create empty file when attempting a YAML export to a non-existing folder (#1600)

* Call `export_journal` before opening file handle
* Use correct exporter class
* Fix unit test

jrnl/plugins/text_exporter.py

@@ -31,18 +31,19 @@ class TextExporter:
     @classmethod
     def write_file(cls, journal, path):
         """Exports a journal into a single file."""
+        export_str = cls.export_journal(journal)
         with open(path, "w", encoding="utf-8") as f:
-            f.write(cls.export_journal(journal))
-            print_msg(
-                Message(
-                    MsgText.JournalExportedTo,
-                    MsgStyle.NORMAL,
-                    {
-                        "path": path,
-                    },
-                )
+            f.write(export_str)
+        print_msg(
+            Message(
+                MsgText.JournalExportedTo,
+                MsgStyle.NORMAL,
+                {
+                    "path": path,
+                },
             )
-            return ""
+        )
+        return ""
 
     @classmethod
     def make_filename(cls, entry):

tests/unit/test_export.py

@@ -1,10 +1,16 @@
 # Copyright © 2012-2022 jrnl contributors
 # License: https://www.gnu.org/licenses/gpl-3.0.html
 
+from unittest import mock
+
 import pytest
 
 from jrnl.exception import JrnlException
+from jrnl.messages import Message
+from jrnl.messages import MsgStyle
+from jrnl.messages import MsgText
 from jrnl.plugins.fancy_exporter import check_provided_linewrap_viability
+from jrnl.plugins.yaml_exporter import YAMLExporter
 
 
 @pytest.fixture()
@@ -28,3 +34,15 @@ class TestFancy:
 
         with pytest.raises(JrnlException):
             check_provided_linewrap_viability(total_linewrap, [content], journal)
+
+
+class TestYaml:
+    @mock.patch("jrnl.plugins.yaml_exporter.YAMLExporter.export_journal")
+    @mock.patch("builtins.open")
+    def test_export_to_nonexisting_folder(self, mock_open, mock_export_journal):
+        mock_export_journal.side_effect = JrnlException(
+            Message(MsgText.YamlMustBeDirectory, MsgStyle.ERROR)
+        )
+        with pytest.raises(JrnlException):
+            YAMLExporter.write_file("journal", "non-existing-path")
+        mock_open.assert_not_called()