add a test game to the catalog defined directly in code

Author: edwardchalstrey1

src/pygambit/catalog/__init__.py

@@ -1,3 +1,3 @@
-from .catalog import PrisonersDilemma, TwoStageMatchingPennies
+from .catalog import PrisonersDilemma, PrisonersDilemmaTestgame, TwoStageMatchingPennies
 
-__all__ = ["PrisonersDilemma", "TwoStageMatchingPennies"]
+__all__ = ["PrisonersDilemma", "TwoStageMatchingPennies", "PrisonersDilemmaTestgame"]

src/pygambit/catalog/catalog.py

@@ -1,5 +1,7 @@
 from pathlib import Path
 
+import numpy as np
+
 from pygambit import Game, read_efg, read_nfg
 
 _CATALOG_DIR = Path(__file__).parent
@@ -12,6 +14,17 @@ class CatalogGame:
     This class serves as a template for specific games in the catalog.
     Calling any subclass will return an instance of the corresponding game.
     """
+
+    def __new__(cls) -> Game:
+        raise NotImplementedError("Subclasses must implement __new__ method")
+
+
+class CatalogGameFromFile(CatalogGame):
+    """
+    Base class for catalog games loaded from files.
+    This class serves as a template for specific games in the catalog.
+    Calling any subclass will return an instance of the corresponding game.
+    """
     # Subclasses must define these
     game_file: str | None = None
 
@@ -39,11 +52,25 @@ def __init_subclass__(cls, **kwargs):
             raise TypeError(f"{cls.__name__} must define 'game_file' class attribute")
 
 
-class PrisonersDilemma(CatalogGame):
+class PrisonersDilemma(CatalogGameFromFile):
     """Prisoner's Dilemma game."""
     game_file = "pd.nfg"
 
 
-class TwoStageMatchingPennies(CatalogGame):
+class TwoStageMatchingPennies(CatalogGameFromFile):
     """Two-Stage Matching Pennies game."""
     game_file = "2smp.efg"
+
+
+class PrisonersDilemmaTestgame(CatalogGame):
+    """A simple test game based on the Prisoner's Dilemma."""
+    def __new__(cls) -> Game:
+        player1_payoffs = np.array([[-1, -3], [0, -2]])
+        player2_payoffs = np.transpose(player1_payoffs)
+
+        g1 = Game.from_arrays(
+            player1_payoffs,
+            player2_payoffs,
+            title="Test Prisoner's Dilemma"
+        )
+        return g1