pytest: port eip spec version checking to a pytest plugin

fillers/conftest.py

@@ -19,7 +19,6 @@
     BlockchainTestFiller,
     Fixture,
     JSONEncoder,
-    ReferenceSpecTypes,
     StateTest,
     StateTestFiller,
     fill_test,
@@ -199,28 +198,6 @@ def eips():
     return []
 
 
-@pytest.fixture(autouse=True, scope="module")
-def reference_spec(request):
-    """
-    Returns the reference spec used for the generated test fixtures in a given
-    module.
-    """
-    module_dict = request.module.__dict__
-    parseable_ref_specs = [
-        ref_spec_type
-        for ref_spec_type in ReferenceSpecTypes
-        if ref_spec_type.parseable_from_module(module_dict)
-    ]
-    if len(parseable_ref_specs) > 0:
-        spec_obj = parseable_ref_specs[0].parse_from_module(module_dict)
-        # TODO: actually raise a warning if the reference spec is outdated
-        return spec_obj
-    else:
-        # TODO: raise a warning if no reference spec is found
-        pass
-    return None
-
-
 SPEC_TYPES: List[Type[BaseTest]] = [StateTest, BlockchainTest]
 SPEC_TYPES_PARAMETERS: List[str] = [
     s.pytest_parameter_name() for s in SPEC_TYPES

pytest.ini

@@ -6,7 +6,9 @@ testpaths =
     fillers/eips/eip3651.py
     fillers/eips/eip3855.py
     fillers/vm/chain_id.py
-addopts = -p pytest_plugins.latest_fork
+addopts = 
+    -p pytest_plugins.latest_fork
+    -p pytest_plugins.spec_version_checker
 markers =
     state_test: test cases that implement a single state transition test
     blockchain_test: test cases that implement block transition tests

src/pytest_plugins/spec_version_checker.py

@@ -0,0 +1,81 @@
+"""
+A pytest plugin that checks that the spec version specified in test/filler
+modules matches that of https://github.com/ethereum/EIPs.
+"""
+import warnings
+
+import pytest
+
+from ethereum_test_tools import ReferenceSpec, ReferenceSpecTypes
+
+IGNORE_PACKAGES = [
+    "vm.",
+    "example.",
+    "security.",
+]
+
+
+class OutdatedReferenceSpec(Warning):
+    """
+    Warning when the spec version found in a filler module is out of date.
+    """
+
+    def __init__(self, filler_module: str, spec_obj: ReferenceSpec):
+        super().__init__(
+            "There is newer version of the spec referenced in filler "
+            f"{filler_module}, tests might be outdated: "
+            f"Spec: {spec_obj.name()}. "
+            "Referenced version: "
+            f"{spec_obj.known_version()}. "
+            "Latest version: "
+            f"{spec_obj.latest_version()}."
+        )
+
+
+class NoReferenceSpecDefined(Warning):
+    """
+    Warning when no spec version was found in a filler module.
+    """
+
+    def __init__(self, filler_module: str):
+        super().__init__(f"No reference spec defined in {filler_module}.")
+
+
+class UnableToCheckReferenceSpec(Warning):
+    """
+    Warnings when the current spec version can not be determined.
+    """
+
+    def __init__(self, filler_module: str, error: Exception):
+        super().__init__(
+            f"Reference spec could not be determined for "
+            f"{filler_module}: {error}."
+        )
+
+
+@pytest.fixture(autouse=True, scope="module")
+def reference_spec(request):
+    """
+    Returns the reference spec used for the generated test fixtures in a
+    given module.
+    """
+    module_dict = request.module.__dict__
+    parseable_ref_specs = [
+        ref_spec_type
+        for ref_spec_type in ReferenceSpecTypes
+        if ref_spec_type.parseable_from_module(module_dict)
+    ]
+    filler_module = request.module.__name__
+    if any(filler_module.startswith(package) for package in IGNORE_PACKAGES):
+        return None
+    if len(parseable_ref_specs) > 0:
+        spec_obj = parseable_ref_specs[0].parse_from_module(module_dict)
+        try:
+            if spec_obj.is_outdated():
+                warnings.warn(OutdatedReferenceSpec(filler_module, spec_obj))
+            return spec_obj
+        except Exception as e:
+            warnings.warn(UnableToCheckReferenceSpec(filler_module, e))
+            return None
+    warnings.warn(NoReferenceSpecDefined(filler_module))
+    return None