Fixing missing base class in reflection docs, adding to reflection te…

…st (#1283)

docs/models.rst

@@ -139,14 +139,19 @@ defining the full model.
 
 Call the :meth:`~.SQLAlchemy.reflect` method on the extension. It will reflect all the
 tables for each bind key. Each metadata's ``tables`` attribute will contain the detected
-table objects.
+table objects. See :doc:`binds` for more details on bind keys.
 
 .. code-block:: python
 
     with app.app_context():
         db.reflect()
 
-    class User:
+    # From the default bind key
+    class Book(db.Model):
+        __table__ = db.metadata.tables["book"]
+
+    # From an "auth" bind key
+    class User(db.Model):
         __table__ = db.metadatas["auth"].tables["user"]
 
 In most cases, it will be more maintainable to define the model classes yourself. You

tests/test_metadata.py

@@ -162,3 +162,17 @@ def test_reflect(app: Flask) -> None:
     db.reflect()
     assert "user" in db.metadata.tables
     assert "post" in db.metadatas["post"].tables
+
+    class User(db.Model):
+        __table__ = db.metadata.tables["user"]
+
+    class Post(db.Model):
+        __table__ = db.metadatas["post"].tables["post"]
+
+    db.session.add(User(id=1))
+    users = db.session.execute(sa.select(User)).scalars().all()
+    assert len(users) == 1
+
+    db.session.add(Post(id=1))
+    posts = db.session.execute(sa.select(Post)).scalars().all()
+    assert len(posts) == 1