Add a Python package for fetch_artifact.

We keep duplicating this function all over the place. Factor it out
and modernize it.

Test: all the test commands named in the readme
Bug: None
Change-Id: I8d90a9c101b9cf83d62d02141f40c6c3666bdf94

python-packages/fetchartifact/tests/__init__.py

@@ -0,0 +1,15 @@
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#

python-packages/fetchartifact/tests/test_fetchartifact.py

@@ -0,0 +1,101 @@
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+"""Tests for fetchartifact."""
+from typing import cast
+
+import pytest
+from aiohttp import ClientResponseError, ClientSession
+from aiohttp.test_utils import TestClient
+from aiohttp.web import Application, Request, Response
+
+from fetchartifact import fetch_artifact, fetch_artifact_chunked
+
+TEST_BUILD_ID = "1234"
+TEST_TARGET = "linux"
+TEST_ARTIFACT_NAME = "output.zip"
+TEST_DOWNLOAD_URL = (
+    f"/android/internal/build/v3/builds/{TEST_BUILD_ID}/{TEST_TARGET}/"
+    f"attempts/latest/artifacts/{TEST_ARTIFACT_NAME}/url"
+)
+TEST_RESPONSE = b"Hello, world!"
+
+
+@pytest.fixture(name="android_ci_client")
+async def fixture_android_ci_client(aiohttp_client: type[TestClient]) -> TestClient:
+    """Fixture for mocking the Android CI APIs."""
+
+    async def download(_request: Request) -> Response:
+        return Response(text=TEST_RESPONSE.decode("utf-8"))
+
+    app = Application()
+    app.router.add_get(TEST_DOWNLOAD_URL, download)
+    return await aiohttp_client(app)  # type: ignore
+
+
+async def test_fetch_artifact(android_ci_client: TestClient) -> None:
+    """Tests that the download URL is queried."""
+    assert TEST_RESPONSE == await fetch_artifact(
+        TEST_TARGET,
+        TEST_BUILD_ID,
+        TEST_ARTIFACT_NAME,
+        cast(ClientSession, android_ci_client),
+        query_url_base="",
+    )
+
+
+async def test_fetch_artifact_chunked(android_ci_client: TestClient) -> None:
+    """Tests that the full file contents are downloaded."""
+    assert [c.encode("utf-8") for c in TEST_RESPONSE.decode("utf-8")] == [
+        chunk
+        async for chunk in fetch_artifact_chunked(
+            TEST_TARGET,
+            TEST_BUILD_ID,
+            TEST_ARTIFACT_NAME,
+            cast(ClientSession, android_ci_client),
+            chunk_size=1,
+            query_url_base="",
+        )
+    ]
+
+
+async def test_failure_raises(android_ci_client: TestClient) -> None:
+    """Tests that fetch failure raises an exception."""
+    with pytest.raises(ClientResponseError):
+        await fetch_artifact(
+            TEST_TARGET,
+            TEST_BUILD_ID,
+            TEST_ARTIFACT_NAME,
+            cast(ClientSession, android_ci_client),
+            query_url_base="/bad",
+        )
+
+    with pytest.raises(ClientResponseError):
+        async for _chunk in fetch_artifact_chunked(
+            TEST_TARGET,
+            TEST_BUILD_ID,
+            TEST_ARTIFACT_NAME,
+            cast(ClientSession, android_ci_client),
+            query_url_base="/bad",
+        ):
+            pass
+
+
+@pytest.mark.requires_network
+async def test_real_artifact() -> None:
+    """Tests with a real artifact. Requires an internet connection."""
+    async with ClientSession() as session:
+        contents = await fetch_artifact("linux", "9945621", "logs/SUCCEEDED", session)
+        assert contents == b"1681499053\n"