feat: Create the Random Choice Oracle

gm_assistant/oracle/random_choice.py

@@ -0,0 +1,38 @@
+# SPDX-FileCopyrightText: 2025 2025
+# SPDX-FileContributor: Gergely Polonkai
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+"""Random Choice Oracle"""
+
+import random
+from typing import Any
+
+from .base import Oracle
+
+
+class RandomChoiceOracle(Oracle):
+    """An Oracle that can choose randomly from a list of possibilities"""
+
+    TYPE_MARKER = "random-choice"
+
+    def __init__(self, oracle_data: dict[str, Any]) -> None:
+        self.choices: list[str] | None = None
+
+        super().__init__(oracle_data)
+
+    def parse_and_validate(self, oracle_data: dict[str, Any]) -> None:
+        super().parse_and_validate(oracle_data)
+
+        if "choices" not in oracle_data:
+            raise KeyError("choices is missing from the data")
+
+        if not oracle_data["choices"]:
+            raise ValueError("Choice list cannot be empty")
+
+        if not isinstance(oracle_data["choices"], list):
+            raise TypeError("choices must be a list")
+
+        self.choices = oracle_data["choices"]
+
+    def generate(self) -> str:
+        return random.choice(self.choices or [])

tests/test_random_choice_oracle.py

@@ -0,0 +1,65 @@
+# SPDX-FileCopyrightText: 2025 2025
+# SPDX-FileContributor: Gergely Polonkai
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+"""Tests for the Random Choice Oracle"""
+
+import pytest
+from pytest_mock import MockerFixture
+
+from gm_assistant.oracle.random_choice import RandomChoiceOracle
+
+TEST_DATA = {
+    "type": "random-choice",
+    "name": "Test Oracle",
+    "source": "Test Source",
+    "choices": ["One", "Two", "Three"],
+}
+
+
+def test_init_missing_choices() -> None:
+    """Test initalising with missing choices"""
+
+    oracle_data = TEST_DATA.copy()
+    del oracle_data["choices"]
+
+    with pytest.raises(KeyError):
+        RandomChoiceOracle(oracle_data)
+
+
+def test_init_empty_choices() -> None:
+    """Test initialising with an empty choice list"""
+
+    oracle_data = TEST_DATA.copy()
+    oracle_data["choices"] = []
+
+    with pytest.raises(ValueError):
+        RandomChoiceOracle(oracle_data)
+
+
+def test_init_nonlist_choices() -> None:
+    """Test initialising with a choice list that is not a list"""
+
+    oracle_data = TEST_DATA.copy()
+    oracle_data["choices"] = {"a": "b"}  # type: ignore[assignment]
+
+    with pytest.raises(TypeError):
+        RandomChoiceOracle(oracle_data)
+
+
+def test_init() -> None:
+    """Test initialisation"""
+
+    oracle = RandomChoiceOracle(TEST_DATA)
+
+    assert oracle.choices == ["One", "Two", "Three"]
+
+
+def test_generate(mocker: MockerFixture) -> None:
+    """Test generate()"""
+
+    mocked_choice = mocker.patch("gm_assistant.oracle.random_choice.random.choice", return_value="Result")
+    oracle = RandomChoiceOracle(TEST_DATA)
+
+    assert oracle.generate() == "Result"
+    mocked_choice.assert_called_once_with(["One", "Two", "Three"])