Added template classes for metamorphic relations and properties

Author: AndrewC19

causal_testing/specification/metamorphic_relation.py

@@ -0,0 +1,38 @@
+from dataclasses import dataclass
+from abc import abstractmethod
+
+
+@dataclass(order=True, frozen=True)
+class MetamorphicRelation:
+    """Class representing a metamorphic relation."""
+
+    @abstractmethod
+    def generate_follow_up(self, source_input_configuration):
+        """Generate a follow-up input configuration from a given source input
+           configuration."""
+        ...
+
+    @abstractmethod
+    def test_oracle(self):
+        """A test oracle i.e. a method that checks correctness of a test."""
+        ...
+
+    @abstractmethod
+    def execute_test(self):
+        """Execute a test for this metamorphic relation."""
+        ...
+
+
+@dataclass(order=True, frozen=True)
+class ShouldCause(MetamorphicRelation):
+    """Class representing a should cause metamorphic relation."""
+
+    def generate_follow_up(self, source_input_configuration):
+        pass
+
+    def test_oracle(self):
+        pass
+
+    def execute_test(self):
+        pass
+

causal_testing/specification/properties.py

@@ -0,0 +1,28 @@
+"""A library of dataclasses for properties implied by a causal DAG."""
+from dataclasses import dataclass
+from typing import Iterable
+
+from causal_specification import Node
+
+
+@dataclass(order=True, frozen=True)
+class ConditionalIndependenceRelation:
+    treatment: Node
+    outcome: Node
+    adjustment_set: Iterable[Node]
+
+    def __str__(self):
+        return f"{self.treatment} _||_ {self.outcome} | {self.adjustment_set}"
+
+
+@dataclass(order=True, frozen=True)
+class CausalRelation:
+    treatment: Node
+    outcome: Node
+    adjustment_set: Iterable[Node] = None
+
+    def __str__(self):
+        formatted_string = f"{self.treatment} --> {self.outcome}"
+        if self.adjustment_set:
+            formatted_string += f" | {self.adjustment_set}"
+        return formatted_string