More tests, fix docs

docs/conf.py

@@ -250,6 +250,7 @@
 rst_epilog = f".. |stac_version| replace:: {STACVersion.DEFAULT_STAC_VERSION}"
 
 nitpick_ignore = [
+    ("py:class", "C"),
     ("py:class", "Datetime"),
     ("py:class", "L"),
     ("py:class", "pystac.summaries.T"),

pystac/collection.py

@@ -718,14 +718,15 @@ def from_items(
         id: str | None = None,
         strategy: HrefLayoutStrategy | None = None,
     ) -> C:
-        """Create a :class:`Collection` from items or an :class:`ItemCollection`.
+        """Create a :class:`Collection` from iterable of items or an
+        :class:`~pystac.ItemCollection`.
 
-        Will try to pull collection attributes from :attr:`ItemCollection.extra_fields`
-        and items when possible.
+        Will try to pull collection attributes from
+        :attr:`~pystac.ItemCollection.extra_fields` and items when possible.
 
         Args:
             items : Iterable of :class:`~pystac.Item` instances to include in the
-                :class:`ItemCollection`. This can be an :class:`pystac.ItemCollection`.
+                :class:`Collection`. This can be a :class:`~pystac.ItemCollection`.
             id : Identifier for the collection. If not set, must be available on the
                 items and they must all match.
             strategy : The layout strategy to use for setting the

tests/test_collection.py

@@ -765,3 +765,58 @@ def test_from_items_without_collection_id() -> None:
 
     collection = Collection.from_items([item1], id="test-collection")
     assert collection.id == "test-collection"
+
+
+def test_from_items_with_collection_ids() -> None:
+    item1 = Item(
+        id="test-item-1",
+        geometry=ARBITRARY_GEOM,
+        bbox=[-10, -20, 0, -10],
+        datetime=datetime(2000, 2, 1, 12, 0, 0, 0, tzinfo=tz.UTC),
+        collection="test-collection-1",
+        properties={},
+    )
+    item2 = Item(
+        id="test-item-2",
+        geometry=ARBITRARY_GEOM,
+        bbox=[-15, -20, 0, -10],
+        datetime=datetime(2000, 2, 1, 13, 0, 0, 0, tzinfo=tz.UTC),
+        collection="test-collection-2",
+        properties={},
+    )
+
+    with pytest.raises(ValueError, match="Collection id must be defined."):
+        Collection.from_items([item1, item2])
+
+    collection = Collection.from_items([item1, item2], id="test-collection")
+    assert collection.id == "test-collection"
+
+
+def test_from_items_with_different_values() -> None:
+    item1 = Item(
+        id="test-item-1",
+        geometry=ARBITRARY_GEOM,
+        bbox=[-10, -20, 0, -10],
+        datetime=datetime(2000, 2, 1, 12, 0, 0, 0, tzinfo=tz.UTC),
+        properties={"title": "Test Item 1"},
+    )
+    item2 = Item(
+        id="test-item-2",
+        geometry=ARBITRARY_GEOM,
+        bbox=[-15, -20, 0, -10],
+        datetime=datetime(2000, 2, 1, 13, 0, 0, 0, tzinfo=tz.UTC),
+        properties={"title": "Test Item 2"},
+    )
+
+    collection = Collection.from_items([item1, item2], id="test_collection")
+    assert collection.title is None
+
+
+def test_from_items_with_providers(sample_item_collection: ItemCollection) -> None:
+    sample_item_collection.extra_fields["providers"] = [{"name": "pystac"}]
+
+    collection = Collection.from_items(sample_item_collection)
+    assert collection.providers and len(collection.providers) == 1
+
+    provider = collection.providers[0]
+    assert provider and provider.name == "pystac"