test: add tests that check extras work as expected

For each extras, it installs the project with that extra, and checks whether the expected extra dependencies have been installed.

tests/conftest.py

@@ -20,6 +20,7 @@
 import tempfile
 from pathlib import Path
 from typing import Generator
+from venv import EnvBuilder
 
 import pytest
 
@@ -42,3 +43,15 @@ def temporary_directory() -> Generator[Path, None, None]:
         os.chdir(tmpdir)
         yield Path(tmpdir)
         os.chdir(old_dir)
+
+
+@pytest.fixture(scope="function")
+def venv_path(  # pylint: disable=redefined-outer-name
+    temporary_directory: Path,
+) -> Generator[Path, None, None]:
+    """Fixture that creates a virtual environment."""
+    env_builder = EnvBuilder(clear=True, with_pip=True)
+    venv_dirpath = temporary_directory / "venv"
+    env_builder.create(env_dir=venv_dirpath)
+    yield venv_dirpath
+    env_builder.clear_directory(venv_dirpath)

tests/test_extras.py

@@ -0,0 +1,57 @@
+# Black-box ABM Calibration Kit (Black-it)
+# Copyright (C) 2021-2023 Banca d'Italia
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+"""This module contains tests for the setuptools extras mechanism."""
+import os
+import subprocess  # nosec
+from pathlib import Path
+from typing import AbstractSet, Mapping
+
+import pytest
+
+from tests.conftest import ROOT_DIR
+
+# Define your extras and expected dependencies here.
+extras_dependencies = {
+    "gp-sampler": {"GPy"},
+    "xgboost-sampler": {"xgboost"},
+}
+
+
+@pytest.mark.not_on_ci
+@pytest.mark.parametrize("extra, dependencies", extras_dependencies.items())
+def test_extras_installation(
+    extra: str, dependencies: Mapping[str, AbstractSet[str]], venv_path: Path
+) -> None:
+    """Test that the extras dependencies are installed as expected."""
+    bin_dirname = "Scripts" if os.name == "nt" else "bin"
+    bin_dir = venv_path / bin_dirname
+    pip_bin_path = bin_dir / "pip"
+
+    # Install the project with the extra
+    subprocess.check_call(  # nosec
+        [pip_bin_path, "install", f".[{extra}]"], cwd=ROOT_DIR
+    )
+
+    # Get a list of installed packages in the virtual environment
+    output = (
+        subprocess.check_output([pip_bin_path, "freeze"]).decode().splitlines()  # nosec
+    )
+    installed_packages = [pkg.split("==")[0] for pkg in output]
+
+    # Check that each dependency for the extra is installed
+    for dependency in dependencies:
+        assert dependency in installed_packages