Allow root to be set during to_dict

There was existing unused arguments for seting the root on
to_dict. This commit implements and tests that the root is set to the
parameter if present, and adds the parameter to ItemCollection, which
itself does not have a root but instead passes the root onto each of
the Items parsed during the to_dict call.

Related to #546

pystac/catalog.py

@@ -963,6 +963,9 @@ def from_dict(
             if link["rel"] != pystac.RelType.SELF or href is None:
                 cat.add_link(Link.from_dict(link))
 
+        if root:
+            cat.set_root(root)
+
         return cat
 
     def full_copy(

pystac/collection.py

@@ -732,6 +732,9 @@ def from_dict(
             for asset_key, asset_dict in assets.items():
                 collection.add_asset(asset_key, Asset.from_dict(asset_dict))
 
+        if root:
+            collection.set_root(root)
+
         return collection
 
     def get_assets(self) -> Dict[str, Asset]:

pystac/item.py

@@ -970,6 +970,9 @@ def from_dict(
             asset.set_owner(item)
             item.assets[k] = asset
 
+        if root:
+            item.set_root(root)
+
         return item
 
     @property

pystac/item_collection.py

@@ -135,7 +135,10 @@ def clone(self) -> "ItemCollection":
 
     @classmethod
     def from_dict(
-        cls, d: Dict[str, Any], preserve_dict: bool = True
+        cls,
+        d: Dict[str, Any],
+        preserve_dict: bool = True,
+        root: Optional[pystac.Catalog] = None,
     ) -> "ItemCollection":
         """Creates a :class:`ItemCollection` instance from a dictionary.
 
@@ -151,7 +154,7 @@ def from_dict(
             raise STACTypeError("Dict is not a valid ItemCollection")
 
         items = [
-            pystac.Item.from_dict(item, preserve_dict=preserve_dict)
+            pystac.Item.from_dict(item, preserve_dict=preserve_dict, root=root)
             for item in d.get("features", [])
         ]
         extra_fields = {k: v for k, v in d.items() if k not in ("features", "type")}

tests/test_catalog.py

@@ -99,6 +99,14 @@ def test_from_dict_preserves_dict(self) -> None:
         _ = Catalog.from_dict(param_dict, preserve_dict=False)
         self.assertNotEqual(param_dict, catalog_dict)
 
+    def test_from_dict_set_root(self) -> None:
+        path = TestCases.get_path("data-files/catalogs/test-case-1/catalog.json")
+        with open(path) as f:
+            cat_dict = json.load(f)
+        root_cat = pystac.Catalog(id="test", description="test desc")
+        collection = Catalog.from_dict(cat_dict, root=root_cat)
+        self.assertIs(collection.get_root(), root_cat)
+
     def test_read_remote(self) -> None:
         # TODO: Move this URL to the main stac-spec repo once the example JSON is fixed.
         catalog_url = (

tests/test_collection.py

@@ -228,6 +228,14 @@ def test_from_dict_preserves_dict(self) -> None:
         _ = Collection.from_dict(param_dict, preserve_dict=False)
         self.assertNotEqual(param_dict, collection_dict)
 
+    def test_from_dict_set_root(self) -> None:
+        path = TestCases.get_path("data-files/examples/hand-0.8.1/collection.json")
+        with open(path) as f:
+            collection_dict = json.load(f)
+        catalog = pystac.Catalog(id="test", description="test desc")
+        collection = Collection.from_dict(collection_dict, root=catalog)
+        self.assertIs(collection.get_root(), catalog)
+
     def test_schema_summary(self) -> None:
         collection = pystac.Collection.from_file(
             TestCases.get_path(

tests/test_item.py

@@ -47,6 +47,12 @@ def test_to_from_dict(self) -> None:
         _ = Item.from_dict(param_dict, preserve_dict=False)
         self.assertNotEqual(param_dict, item_dict)
 
+    def test_from_dict_set_root(self) -> None:
+        item_dict = self.get_example_item_dict()
+        catalog = pystac.Catalog(id="test", description="test desc")
+        item = Item.from_dict(item_dict, root=catalog)
+        self.assertIs(item.get_root(), catalog)
+
     def test_set_self_href_does_not_break_asset_hrefs(self) -> None:
         cat = TestCases.test_case_2()
         for item in cat.get_all_items():

tests/test_item_collection.py

@@ -169,3 +169,10 @@ def test_from_dict_preserves_dict(self) -> None:
         # non-default parameter
         _ = ItemCollection.from_dict(param_dict, preserve_dict=False)
         self.assertNotEqual(param_dict, self.item_collection_dict)
+
+    def test_from_dict_sets_root(self) -> None:
+        param_dict = deepcopy(self.item_collection_dict)
+        catalog = pystac.Catalog(id="test", description="test desc")
+        item_collection = ItemCollection.from_dict(param_dict, root=catalog)
+        for item in item_collection.items:
+            self.assertEqual(item.get_root(), catalog)