Add parity tests for model_alias vs bare-string registry aliases

ccflow/tests/config/conf_flow_alias.yaml

@@ -0,0 +1,29 @@
+# Parity config: a registered source referenced three equivalent ways.
+#
+# In ccflow a bare string field value is resolved from the model registry, so an
+# explicit `model_alias` wrapper, a bare-string alias, and a root-relative `/name`
+# alias should all dereference to the SAME registered model instance.
+
+alias_source:
+    _target_: ccflow.tests.flow_model_hydra_fixtures.data_source
+    base_value: 100
+
+# 1. Explicit Hydra wrapper form.
+via_model_alias:
+    _target_: ccflow.tests.flow_model_hydra_fixtures.data_transformer
+    source:
+        _target_: ccflow.compose.model_alias
+        model_name: alias_source
+    factor: 3
+
+# 2. Bare-string registry alias.
+via_bare_string:
+    _target_: ccflow.tests.flow_model_hydra_fixtures.data_transformer
+    source: alias_source
+    factor: 3
+
+# 3. Root-relative registry alias.
+via_root_relative:
+    _target_: ccflow.tests.flow_model_hydra_fixtures.data_transformer
+    source: /alias_source
+    factor: 3

ccflow/tests/test_flow_model_alias.py

@@ -0,0 +1,46 @@
+"""Parity tests: model_alias vs bare-string vs root-relative registry aliases.
+
+In ccflow a bare string field value is resolved from the model registry, so an explicit
+`ccflow.compose.model_alias` wrapper, a bare-string alias, and a root-relative `/name`
+alias should all dereference to the same registered model instance. `model_alias` is a
+Hydra convenience for the existing bare-string convention, not a separate mechanism.
+"""
+
+from pathlib import Path
+
+from ccflow import CallableModel, ModelRegistry
+
+ALIAS_CONFIG_PATH = str(Path(__file__).parent / "config" / "conf_flow_alias.yaml")
+
+
+def setup_function():
+    ModelRegistry.root().clear()
+
+
+def teardown_function():
+    ModelRegistry.root().clear()
+
+
+def test_alias_forms_resolve_to_same_instance():
+    registry = ModelRegistry.root()
+    registry.load_config_from_path(ALIAS_CONFIG_PATH)
+
+    source = registry["alias_source"]
+    via_model_alias = registry["via_model_alias"]
+    via_bare_string = registry["via_bare_string"]
+    via_root_relative = registry["via_root_relative"]
+
+    # Each `source` must be the registered model instance, not a literal string.
+    assert isinstance(via_bare_string.source, CallableModel)
+    assert via_model_alias.source is source
+    assert via_bare_string.source is source
+    assert via_root_relative.source is source
+
+
+def test_alias_forms_compute_identically():
+    registry = ModelRegistry.root()
+    registry.load_config_from_path(ALIAS_CONFIG_PATH)
+
+    results = [registry[name].flow.compute(value=5).value for name in ("via_model_alias", "via_bare_string", "via_root_relative")]
+    # data_source(base_value=100)(value=5) -> 105; data_transformer(factor=3) -> 315
+    assert results == [315, 315, 315]