tests: Rework CLI tests

The current tests do not take into account whether the `gpg` package has
been installed or not. If it is missing, the tests should be skipped.

Furthermore, the output of the tests must be checked in order to decide
whether tests fail due to an exception or whether the desired error message
is displayed.

Signed-off-by: Jörg Sommer <[email protected]>

tests/test_CLI.py

@@ -21,7 +21,6 @@
 import sys
 import tempfile
 import tests.helpers
-import gpg
 import shutil
 
 
@@ -39,10 +38,14 @@ def test_valid_signature(self):
                 self.tmpfile,
             ],
             stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
+            stderr=subprocess.PIPE,
             check=False,
         )
-        self.assertEqual(completed_process.returncode, 0, completed_process.stdout)
+        self.assertEqual(completed_process.returncode, 0)
+        self.assertEqual(completed_process.stdout, b"")
+        self.assertIn(
+            b"successfully verified bmap file signature", completed_process.stderr
+        )
 
     def test_unknown_signer(self):
         completed_process = subprocess.run(
@@ -57,10 +60,12 @@ def test_unknown_signer(self):
                 self.tmpfile,
             ],
             stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
+            stderr=subprocess.PIPE,
             check=False,
         )
-        self.assertEqual(completed_process.returncode, 1, completed_process.stdout)
+        self.assertEqual(completed_process.returncode, 1)
+        self.assertEqual(completed_process.stdout, b"")
+        self.assertIn(b"discovered a BAD GPG signature", completed_process.stderr)
 
     def test_wrong_signature(self):
         completed_process = subprocess.run(
@@ -75,10 +80,12 @@ def test_wrong_signature(self):
                 self.tmpfile,
             ],
             stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
+            stderr=subprocess.PIPE,
             check=False,
         )
-        self.assertEqual(completed_process.returncode, 1, completed_process.stdout)
+        self.assertEqual(completed_process.returncode, 1)
+        self.assertEqual(completed_process.stdout, b"")
+        self.assertIn(b"discovered a BAD GPG signature", completed_process.stderr)
 
     def test_wrong_signature_uknown_signer(self):
         completed_process = subprocess.run(
@@ -93,10 +100,12 @@ def test_wrong_signature_uknown_signer(self):
                 self.tmpfile,
             ],
             stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
+            stderr=subprocess.PIPE,
             check=False,
         )
-        self.assertEqual(completed_process.returncode, 1, completed_process.stdout)
+        self.assertEqual(completed_process.returncode, 1)
+        self.assertEqual(completed_process.stdout, b"")
+        self.assertIn(b"discovered a BAD GPG signature", completed_process.stderr)
 
     def test_clearsign(self):
         completed_process = subprocess.run(
@@ -109,12 +118,21 @@ def test_clearsign(self):
                 self.tmpfile,
             ],
             stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT,
+            stderr=subprocess.PIPE,
             check=False,
         )
-        self.assertEqual(completed_process.returncode, 0, completed_process.stdout)
+        self.assertEqual(completed_process.returncode, 0)
+        self.assertEqual(completed_process.stdout, b"")
+        self.assertIn(
+            b"successfully verified bmap file signature", completed_process.stderr
+        )
 
     def setUp(self):
+        try:
+            import gpg
+        except ImportError:
+            self.skipTest("python module 'gpg' missing")
+
         os.makedirs("tests/test-data/signatures", exist_ok=True)
         for gnupghome, userid in [
             ("tests/test-data/gnupg/", "correct <[email protected]>"),