perf: Optimize len(schema)

Signed-off-by: Dmitry Dygalo <dmitry@dygalo.dev>

docs/changelog.rst

@@ -13,8 +13,8 @@ Changelog
 
 **Performance**
 
-- Optimize `get_operation_by_id` method performance and reduce memory usage.
-- Optimize `get_operation_by_reference` method performance.
+- Optimize ``get_operation_by_id`` method performance and reduce memory usage.
+- Optimize ``get_operation_by_reference`` method performance.
 - Less copying during schema traversal.
 
 .. _v3.28.1:

src/schemathesis/schemas.py

@@ -112,7 +112,7 @@ def on_missing_operation(self, item: str, exc: KeyError) -> NoReturn:
         raise NotImplementedError
 
     def __len__(self) -> int:
-        return len(self.operations)
+        return self.operations_count
 
     def hook(self, hook: str | Callable) -> Callable:
         return self.hooks.register(hook)
@@ -446,7 +446,7 @@ def as_strategy(
         **kwargs: Any,
     ) -> SearchStrategy:
         """Build a strategy for generating test cases for all defined API operations."""
-        assert len(self.operations) > 0, "No API operations found"
+        assert len(self) > 0, "No API operations found"
         strategies = [
             operation.as_strategy(
                 hooks=hooks,

test/test_recoverable_errors.py

@@ -109,7 +109,7 @@ def test_in_cli(testdir, cli, open_api_3_schema_with_recoverable_errors, workers
 
 def test_direct_access(schema):
     # Then valid operations should be accessible via the mapping interface
-    assert len(schema) == 1
+    assert len(schema) == 2
     assert schema["/bar"]["GET"]