fix: create dir before writing stac item

CHANGELOG.md

@@ -12,6 +12,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 - `open_href` ([#123](https://github.com/stac-utils/stac-asset/pull/123))
 
+### Fixed
+
+- Directory for writing Item JSON is always created ([#152](https://github.com/stac-utils/stac-asset/pull/152))
+
 ## [0.2.3] - 2023-10-20
 
 ### Added

src/stac_asset/_functions.py

@@ -238,6 +238,7 @@ async def download_item(
     if self_href:
         make_asset_hrefs_relative(item)
         d = item.to_dict(include_self_link=True, transform_hrefs=False)
+        os.makedirs(os.path.dirname(self_href), exist_ok=True)
         with open(self_href, "w") as f:
             json.dump(d, f)
 

tests/test_functions.py

@@ -74,6 +74,18 @@ async def test_download_missing_asset_delete(tmp_path: Path, item: Item) -> None
     assert "does-not-exist" not in item.assets
 
 
+async def test_download_nonexistent_asset(tmp_path: Path, item: Item) -> None:
+    # this previously had a bug where the code assumed the directory had
+    # been created by downloading the assets when trying to write the item json,
+    # but it hadn't, so a failure occurred
+    await stac_asset.download_item(
+        item,
+        tmp_path / "dir-that-doesnt-exist",
+        file_name="item.json",
+        config=Config(include=["non-existent-asset"]),
+    )
+
+
 async def test_download_missing_asset_fail_fast(tmp_path: Path, item: Item) -> None:
     item.assets["does-not-exist"] = Asset("not-a-file.md5")
     with pytest.raises(FileNotFoundError):