test: Add test for parsing circular env vars

The method never returns anything so we should not receive output.

test/test_configuration.py

@@ -7,6 +7,7 @@ import pytest
 
 from topen import TConf, build_config
 
+
 class TestTConf:
     def test_paths_are_expanded(self):
         cfg = TConf.from_dict(
@@ -62,6 +63,17 @@ class TestBuildConfigPrecedence:
         cfg = build_config()
         assert cfg.notes_ext == "from-env"
 
+    def test_circular_env_vars(self, isolate_env, monkeypatch, fake_id):
+        """Test environment variables with circular references."""
+        for k, v in {
+            "TOPEN_NOTES_DIR": "$TOPEN_NOTES_DIR/subdir",
+            "EDITOR": "${EDITOR}_backup",
+        }.items():
+            monkeypatch.setenv(k, v)
+        cfg = build_config()
+        assert cfg.notes_dir == Path("$TOPEN_NOTES_DIR/subdir/subdir")
+        assert cfg.notes_editor == "nano"
+
     def test_cli_overrides_env(self, fake_rc, monkeypatch, isolate_env):
         fake_rc.write_text("notes.ext=from-rc\n")
         monkeypatch.setenv("TOPEN_NOTES_EXT", "from-env")

test/test_problems_edge_cases.py

@@ -0,0 +1,64 @@
+import configparser
+import os
+import tempfile
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+from topen import _ensure_parent_dir, get_notes_file, get_task, parse_env, parse_rc
+
+
+class TestFSEdgeCases:
+    """Test edge cases for TaskWarrior integration and file system operations."""
+
+    def test_nonexistent_task_id(self, tmp_path):
+        """Test raised error for non-existent task IDs."""
+        with patch("tasklib.TaskWarrior") as mock_tw:
+            mock_tw.return_value.tasks.get.side_effect = [
+                Exception("Task not found"),
+            ]
+
+            with pytest.raises(
+                Exception,
+                match="Task matching query does not exist. Lookup parameters were {'uuid': '999999'}",
+            ):
+                get_task("999999", tmp_path)
+
+    def test_read_only_notes_directory(self, tmp_path):
+        """Test raised error when notes directory is read-only."""
+        notes_dir = tmp_path / "read_only_notes"
+        notes_dir.mkdir()
+
+        # Make directory read-only
+        os.chmod(notes_dir, 0o444)
+
+        fpath = notes_dir / "subdir_cant_be_written" / "uuid.md"
+        with pytest.raises(PermissionError):
+            _ensure_parent_dir(fpath)
+
+    def test_symlink_notes_directory(self, tmp_path):
+        """Test behavior with symlinked notes directory,
+        reading the linked dir instead of the real dir. """
+        real_dir = tmp_path / "real_notes"
+        real_dir.mkdir()
+        link_dir = tmp_path / "linked_notes"
+        link_dir.symlink_to(real_dir)
+
+        fpath = get_notes_file("test-uuid", link_dir, "md")
+        assert fpath.parent == link_dir
+
+    def test_empty_taskrc_file(self, tmp_path):
+        """Test functional handling of empty taskrc file."""
+        fake_rc: Path = tmp_path / "empty.taskrc"
+        fake_rc.touch()
+        assert parse_rc(fake_rc) == {}
+
+    def test_taskrc_with_invalid_syntax(self, tmp_path):
+        """Test functional handling of taskrc with invalid syntax."""
+        invalid_rc: Path = tmp_path / "invalid.taskrc"
+        invalid_rc.write_text(
+            "invalid line == [MMMM] with too many = = equals sign\ndata.location = valid_value\n"
+        )
+
+        assert parse_rc(invalid_rc)

topen.py

@@ -51,19 +51,24 @@ def main(cfg: "TConf | None" = None, io: "_IO | None" = None) -> int:
         io = _IO(quiet=cfg.notes_quiet)
 
     if not cfg.task_id:
-        _ = io.err("Please provide task ID as argument.\n")
+        io.err("Please provide task ID as argument.\n")
         return 1
 
     try:
         task = get_task(id=cfg.task_id, data_location=cfg.task_data)
         uuid = cast(str, task["uuid"])
     except Task.DoesNotExist:
-        _ = io.err(f"Could not find task for ID: {cfg.task_id}.\n")
+        io.err(f"Could not find task for ID: {cfg.task_id}.\n")
         return 1
 
     fpath = get_notes_file(uuid, notes_dir=cfg.notes_dir, notes_ext=cfg.notes_ext)
 
+    try:
         _ensure_parent_dir(fpath)
+    except PermissionError:
+        io.err(f"Could not write required directories for path: {fpath}.\n")
+        return 1
+
     io.out(f"Editing note: {fpath}")
     open_editor(fpath, editor=cfg.notes_editor, io=io)