tests: create integration tests for talking to snapd

craft_parts/packages/snaps.py

@@ -19,6 +19,7 @@
 import contextlib
 import logging
 import os
+import pathlib
 import subprocess
 import sys
 from collections.abc import Iterator, Sequence
@@ -200,7 +201,7 @@ def is_valid(self) -> bool:
         store_channels = self._get_store_channels()
         return self.channel in store_channels
 
-    def download(self, *, directory: str | None = None) -> None:
+    def download(self, *, directory: str | pathlib.Path | None = None) -> None:
         """Download a given snap."""
         # We use the `snap download` command here on recommendation
         # of the snapd team.
@@ -270,7 +271,7 @@ def refresh(self) -> None:
         self._is_installed = None
 
 
-def download_snaps(*, snaps_list: Sequence[str], directory: str) -> None:
+def download_snaps(*, snaps_list: Sequence[str], directory: str | pathlib.Path) -> None:
     """Download snaps of the format <snap-name>/<channel> into directory.
 
     The target directory is created if it does not exist.

tests/conftest.py

@@ -45,6 +45,12 @@ def new_dir(monkeypatch, tmpdir):
     return tmpdir
 
 
+@pytest.fixture
+def new_path(monkeypatch, tmp_path):
+    monkeypatch.chdir(tmp_path)
+    return tmp_path
+
+
 @pytest.fixture
 def tmp_homedir_path():
     """A non-hidden temporary directory in the user's home directory.

tests/integration/packages/test_snaps.py

@@ -0,0 +1,57 @@
+# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
+#
+# Copyright 2024 Canonical Ltd.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License version 3 as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""Integration tests for interacting with snapd."""
+
+import pathlib
+from collections.abc import Sequence
+
+import pytest
+import pytest_check  # type: ignore[import]
+from craft_parts.packages import snaps
+
+
+def test_get_installed_snaps_success():
+    """Test that get_installed_snaps returns a list of snaps."""
+    actual = snaps.get_installed_snaps()
+
+    for snap in actual:
+        name, _, revision = snap.partition("=")
+        pytest_check.is_true(len(name) >= 1)
+        if revision.startswith("x"):
+            # Locally installed snaps should be of the form "x<int>"
+            with pytest_check.check():
+                int(revision[1:])
+        else:
+            # Store-instaled snaps should simply have an integer revision.
+            with pytest_check.check():
+                int(revision)
+
+
+@pytest.mark.parametrize(
+    "snaps_list",
+    [
+        {"snapcraft", "ruff"},
+        {"snapcraft/7.x/stable"},
+    ],
+)
+def test_download_snaps_success(new_path: pathlib.Path, snaps_list: Sequence[str]):
+
+    snaps.download_snaps(snaps_list=snaps_list, directory=new_path)
+
+    for snap in snaps_list:
+        snap_name, _, snap_channel = snap.partition("/")
+        assert len(list(new_path.glob(f"{snap_name}*.snap"))) == 1
+        assert len(list(new_path.glob(f"{snap_name}*.assert"))) == 1