test: add integration test for Chroot.run()

This commit adds a test that is more "integration"-ish in style
to make sure that the actual return code of a command is returned
via chroot.

test/mod/test_util_chroot.py

@@ -5,6 +5,7 @@
 import os
 from unittest.mock import call, patch
 
+from osbuild.testutil import mock_command
 from osbuild.util.chroot import Chroot
 
 
@@ -41,3 +42,15 @@ def test_chroot_context(mocked_run, tmp_path):
         call(["umount", "--lazy", os.fspath(tmp_path / "dev")], check=False),
         call(["umount", "--lazy", os.fspath(tmp_path / "sys")], check=False),
     ]
+
+
+def test_chroot_integration(tmp_path):
+    # drop the first two arguments ("chroot", "target-dir") from our fake
+    # chroot
+    fake_chroot = r'exec "${@:2}"'
+    with mock_command("mount", ""), mock_command("umount", ""), mock_command("chroot", fake_chroot):
+        with Chroot(os.fspath(tmp_path)) as chroot:
+            ret = chroot.run(["/bin/true"], check=True)
+            assert ret.returncode == 0
+            ret = chroot.run(["/bin/false"], check=False)
+            assert ret.returncode == 1