package: Implement installing packages in the component

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/package.py

@@ -6,6 +6,7 @@ Framework for installing and updating distribution packages
 import json
 import logging
 import subprocess
+import sys
 import threading
 from typing import Union
 
@@ -50,6 +51,14 @@ class Packages(app.FollowerComponent):
         """Return the list of packages managed by this component."""
         return self._packages
 
+    def setup(self, old_version):
+        """Install the packages."""
+        # TODO: Drop the need for setup helper.
+        module_name = self.app.__module__
+        module = sys.modules[module_name]
+        helper = module.setup_helper
+        helper.install(self.packages, skip_recommends=self.skip_recommends)
+
 
 class PackageException(Exception):
     """A package operation has failed."""

plinth/tests/test_package.py

@@ -3,13 +3,16 @@
 Test module for package module.
 """
 
-from unittest.mock import call, patch
+from unittest.mock import Mock, call, patch
 
 import pytest
 
+from plinth.app import App
 from plinth.errors import ActionError
 from plinth.package import Packages, packages_installed, remove
 
+setup_helper = Mock()
+
 
 def test_packages_init():
     """Test initialization of packages component."""
@@ -26,6 +29,31 @@ def test_packages_init():
     assert component.skip_recommends
 
 
+def test_packages_setup():
+    """Test setting up packages component."""
+
+    class TestApp(App):
+        """Test app"""
+        app_id = 'test-app'
+
+    component = Packages('test-component', ['foo1', 'bar1'])
+    app = TestApp()
+    app.add(component)
+    setup_helper.reset_mock()
+    app.setup(old_version=3)
+    setup_helper.install.assert_has_calls(
+        [call(['foo1', 'bar1'], skip_recommends=False)])
+
+    component = Packages('test-component', ['foo2', 'bar2'],
+                         skip_recommends=True)
+    app = TestApp()
+    app.add(component)
+    setup_helper.reset_mock()
+    app.setup(old_version=3)
+    setup_helper.install.assert_has_calls(
+        [call(['foo2', 'bar2'], skip_recommends=True)])
+
+
 def test_packages_installed():
     """Test packages_installed()."""
     # list as input