feat: Add an Oracle base class

gm_assistant/oracle/__init__.py

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+# SPDX-FileCopyrightText: 2025 2025
+# SPDX-FileContributor: Gergely Polonkai
+#
+# SPDX-License-Identifier: GPL-3.0-or-later

gm_assistant/oracle/base.py

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+# SPDX-FileCopyrightText: 2025 2025
+# SPDX-FileContributor: Gergely Polonkai
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+"""Oracle base class and related utilities"""
+
+from abc import ABCMeta, abstractmethod
+from typing import Any
+
+
+class Oracle(metaclass=ABCMeta):  # pylint: disable=too-few-public-methods
+    """Base class for Oracles"""
+
+    TYPE_MARKER: str
+
+    def __init__(self, oracle_data: dict[str, Any]) -> None:
+        self.name: str | None = None
+        self.source: str | None = None
+        self.source_url: str | None = None
+        self.parse_and_validate(oracle_data)
+
+    def parse_and_validate(self, oracle_data: dict[str, Any]) -> None:
+        """Parse and validate ``oracle_data``, essentially setting up the Oracle"""
+
+        if "type" not in oracle_data:
+            raise KeyError("type")
+
+        if "name" not in oracle_data:
+            raise KeyError("name")
+
+        if "source" not in oracle_data:
+            raise KeyError("source")
+
+        if (data_type := oracle_data["type"]) != self.TYPE_MARKER:
+            raise TypeError(f"This class can only handle {self.TYPE_MARKER} data, not {data_type}")
+
+        self.name = oracle_data["name"]
+        self.source = oracle_data["source"]
+        self.source_url = oracle_data.get("source-url")
+
+    @abstractmethod
+    def generate(self) -> str:  # pragma: no cover
+        """Make the Oracle do its work"""
+
+        raise NotImplementedError()

tests/test_oracle_base.py

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+# SPDX-FileCopyrightText: 2025 2025
+# SPDX-FileContributor: Gergely Polonkai
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+"""Tests for the base Oracle class"""
+
+from typing import Literal
+
+import pytest
+
+from gm_assistant.oracle.base import Oracle
+
+TEST_ORACLE_DATA = {
+    "type": "test-oracle",
+    "name": "Test Oracle",
+    "source": "Test Source",
+}
+
+
+class OracleTest(Oracle):
+    """Test Oracle class"""
+
+    TYPE_MARKER = "test-oracle"
+
+    def generate(self) -> str:  # pragma: no cover
+        return "Something"
+
+
+@pytest.mark.parametrize("missing", ["type", "name", "source"])
+def test_missing_data(missing: Literal["type", "name", "source"]) -> None:
+    """Test if oracle_data doesn’t have a type"""
+
+    oracle_data = TEST_ORACLE_DATA.copy()
+    del oracle_data[missing]
+
+    with pytest.raises(KeyError):
+        OracleTest(oracle_data)
+
+
+def test_incorrect_type() -> None:
+    """Test if the type in the oracle data doesn’t match the class’ TYPE_MARKER"""
+
+    oracle_data = TEST_ORACLE_DATA.copy()
+    oracle_data["type"] = "something-else"
+
+    with pytest.raises(TypeError):
+        OracleTest(oracle_data)
+
+
+def test_init() -> None:
+    """Test if initialisation succeeds with valid data"""
+
+    oracle = OracleTest(TEST_ORACLE_DATA)
+
+    assert oracle.name == "Test Oracle"
+    assert oracle.source == "Test Source"
+    assert oracle.source_url is None