Use Popen.communicate to get stdout from subprocess

libagent/gpg/keyring.py

@@ -17,8 +17,11 @@ log = logging.getLogger(__name__)
 def check_output(args, env=None, sp=subprocess):
     """Call an external binary and return its stdout."""
     log.debug('calling %s with env %s', args, env)
-    output = sp.check_output(args=args, env=env)
+    p = sp.Popen(args=args, env=env, stdin=sp.PIPE, stdout=sp.PIPE, stderr=sp.PIPE)
+    (output, error) = p.communicate()
     log.debug('output: %r', output)
+    if error:
+        log.debug('error: %r', error)
     return output
 
 

libagent/gpg/tests/test_keyring.py

@@ -53,6 +53,14 @@ class FakeSocket:
         self.tx.write(data)
 
 
+def mock_subprocess(output, error=b''):
+    sp = mock.Mock(spec=['Popen', 'PIPE'])
+    p = mock.Mock(spec=['communicate'])
+    sp.Popen.return_value = p
+    p.communicate.return_value = (output, error)
+    return sp
+
+
 def test_sign_digest():
     sock = FakeSocket()
     sock.rx.write(b'OK Pleased to meet you, process XYZ\n')
@@ -61,10 +69,8 @@ def test_sign_digest():
     sock.rx.seek(0)
     keygrip = '1234'
     digest = b'A' * 32
-    sp = mock.Mock(spec=['check_output'])
-    sp.check_output.return_value = '/dev/pts/0'
     sig = keyring.sign_digest(sock=sock, keygrip=keygrip,
-                              digest=digest, sp=sp,
+                              digest=digest, sp=mock_subprocess('/dev/pts/0'),
                               environ={'DISPLAY': ':0'})
     assert sig == (0x30313233343536373839414243444546,)
     assert sock.tx.getvalue() == b'''RESET
@@ -85,8 +91,7 @@ def test_iterlines():
 
 
 def test_get_agent_sock_path():
-    sp = mock.Mock(spec=['check_output'])
-    sp.check_output.return_value = b'''sysconfdir:/usr/local/etc/gnupg
+    sp = mock_subprocess(b'''sysconfdir:/usr/local/etc/gnupg
 bindir:/usr/local/bin
 libexecdir:/usr/local/libexec
 libdir:/usr/local/lib/gnupg
@@ -96,6 +101,6 @@ dirmngr-socket:/run/user/1000/gnupg/S.dirmngr
 agent-ssh-socket:/run/user/1000/gnupg/S.gpg-agent.ssh
 agent-socket:/run/user/1000/gnupg/S.gpg-agent
 homedir:/home/roman/.gnupg
-'''
+''')
     expected = b'/run/user/1000/gnupg/S.gpg-agent'
     assert keyring.get_agent_sock_path(sp=sp) == expected