add tests

tests/integration/test_agent.py

@@ -10,6 +10,9 @@
 import jenkinsapi.jenkins
 from juju.application import Application
 from juju.model import Model
+from juju.unit import Unit
+
+from charm_state import APT_PACKAGES_CONFIG
 
 from .conftest import NUM_AGENT_UNITS, assert_job_success
 
@@ -63,3 +66,21 @@ async def test_agent_relation(
     assert len(nodes.values()) == NUM_AGENT_UNITS + 1
 
     assert_job_success(jenkins_client, jenkins_agent_application.name, "machine")
+
+
+async def test_agent_packages(
+    model: Model,
+    jenkins_agent_application: Application,
+):
+    """
+    arrange: given a jenkins agent application.
+    act: when the apt-packages configuration is set.
+    assert: the defined packages are installed.
+    """
+    await jenkins_agent_application.set_config({APT_PACKAGES_CONFIG: "bzr, iputils-ping"})
+    await model.wait_for_idle()
+
+    unit: Unit = jenkins_agent_application.units[0]
+
+    assert "/usr/bin/bzr" == await unit.ssh(["which", "bzr"])
+    assert "/usr/bin/ping" == await unit.ssh(["which", "ping"])

tests/unit/test_service.py

@@ -17,6 +17,7 @@
 import service
 from charm import JenkinsAgentCharm
 from charm_state import AGENT_RELATION
+from service import JenkinsAgentService, PackageInstallError
 
 
 @pytest.mark.parametrize(
@@ -72,6 +73,39 @@ def test_on_install(harness: ops.testing.Harness, monkeypatch: pytest.MonkeyPatc
     assert harness.charm.unit.status.name == ops.BlockedStatus.name
 
 
+def test_on_install_packages_fail(monkeypatch: pytest.MonkeyPatch):
+    """
+    arrange: Given a monkeypatched apt lib that raises an error.
+    act: when install_apt_packages is called.
+    assert: PackageInstallError is raised.
+    """
+    monkeypatch.setattr(apt, "add_package", MagicMock(side_effect=apt.PackageNotFoundError))
+
+    with pytest.raises(PackageInstallError):
+        JenkinsAgentService.install_apt_packages(["hello", "world"])
+
+
+@pytest.mark.parametrize(
+    "packages",
+    [
+        pytest.param(tuple(), id="No packages"),
+        pytest.param(tuple("hello", "world"), id="Has packages"),
+    ],
+)
+def test_on_install_packages(monkeypatch: pytest.MonkeyPatch, packages: tuple[str, ...]):
+    """
+    arrange: Given a monkeypatched apt lib and list of packages to install.
+    act: when install_apt_packages is called.
+    assert: package install call is made.
+    """
+    monkeypatch.setattr(apt, "add_package", (apt_mock := MagicMock()))
+
+    JenkinsAgentService.install_apt_packages(packages)
+
+    if packages:
+        apt_mock.assert_has_calls()
+
+
 def test_restart_service(
     harness: ops.testing.Harness,
     monkeypatch: pytest.MonkeyPatch,