apt.py: use CalledProcessError.stderr in exceptions instead of output…

…/stdout
canonical · Dec 15, 2023 · b9e6fa3 · b9e6fa3
1 parent 405948a
commit b9e6fa3
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Showing 2 changed files with 24 additions and 3 deletions.
diff --git a/lib/charms/operator_libs_linux/v0/apt.py b/lib/charms/operator_libs_linux/v0/apt.py
@@ -253,7 +253,7 @@ def _apt(
             subprocess.run(_cmd, capture_output=True, check=True, env=env)
         except CalledProcessError as e:
             raise PackageError(
-                "Could not {} package(s) [{}]: {}".format(command, [*package_names], e.output)
+                "Could not {} package(s) [{}]: {}".format(command, [*package_names], e.stderr)
             ) from None
 
     def _add(self) -> None:
@@ -476,7 +476,7 @@ def from_apt_cache(
             )
         except CalledProcessError as e:
             raise PackageError(
-                "Could not list packages in apt-cache: {}".format(e.output)
+                "Could not list packages in apt-cache: {}".format(e.stderr)
             ) from None
 
         pkg_groups = output.strip().split("\n\n")

diff --git a/tests/unit/test_apt.py b/tests/unit/test_apt.py
@@ -275,6 +275,24 @@ def test_can_load_from_apt_cache_multi_arch(self, mock_subprocess):
         self.assertEqual(tester.fullversion, "1:1.2.3-4.i386")
         self.assertEqual(str(tester.version), "1:1.2.3-4")
 
+    @patch("charms.operator_libs_linux.v0.apt.check_output")
+    def test_will_throw_apt_cache_errors(self, mock_subprocess):
+        mock_subprocess.side_effect = [
+            "amd64",
+            subprocess.CalledProcessError(
+                returncode=100,
+                cmd=["apt-cache", "show", "mocktester"],
+                stderr="N: Unable to locate package mocktester",
+            ),
+        ]
+
+        with self.assertRaises(apt.PackageError) as ctx:
+            apt.DebianPackage.from_apt_cache("mocktester", arch="i386")
+
+        self.assertEqual("<charms.operator_libs_linux.v0.apt.PackageError>", ctx.exception.name)
+        self.assertIn("Could not list packages in apt-cache", ctx.exception.message)
+        self.assertIn("Unable to locate package", ctx.exception.message)
+
     @patch("charms.operator_libs_linux.v0.apt.check_output")
     @patch("charms.operator_libs_linux.v0.apt.subprocess.run")
     @patch("os.environ.copy")
@@ -322,7 +340,9 @@ def test_can_run_apt_commands(
     @patch("charms.operator_libs_linux.v0.apt.subprocess.run")
     def test_will_throw_apt_errors(self, mock_subprocess_call, mock_subprocess_output):
         mock_subprocess_call.side_effect = subprocess.CalledProcessError(
-            returncode=1, cmd=["apt-get", "-y", "install"]
+            returncode=1,
+            cmd=["apt-get", "-y", "install"],
+            stderr="E: Unable to locate package mocktester",
         )
         mock_subprocess_output.side_effect = [
             "amd64",
@@ -339,6 +359,7 @@ def test_will_throw_apt_errors(self, mock_subprocess_call, mock_subprocess_outpu
 
         self.assertEqual("<charms.operator_libs_linux.v0.apt.PackageError>", ctx.exception.name)
         self.assertIn("Could not install package", ctx.exception.message)
+        self.assertIn("Unable to locate package", ctx.exception.message)
 
     def test_can_compare_versions(self):
         old_version = apt.Version("1.0.0", "")