greenio: socket.recv() could return str; Thanks to jerzyk

It must always return bytes.
#245

eventlet/greenio/base.py

@@ -315,7 +315,7 @@ def recv(self, buflen, flags=0):
                 if get_errno(e) in SOCKET_BLOCKING:
                     pass
                 elif get_errno(e) in SOCKET_CLOSED:
-                    return ''
+                    return b''
                 else:
                     raise
             try:

tests/__init__.py

@@ -292,13 +292,15 @@ def get_database_auth():
     return retval
 
 
-def run_python(path):
+def run_python(path, env=None):
     if not path.endswith('.py'):
         path += '.py'
     path = os.path.abspath(path)
     src_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
     new_env = os.environ.copy()
     new_env['PYTHONPATH'] = os.pathsep.join(sys.path + [src_dir])
+    if env:
+        new_env.update(env)
     p = subprocess.Popen(
         [sys.executable, path],
         env=new_env,
@@ -310,15 +312,18 @@ def run_python(path):
     return output
 
 
-def run_isolated(path, prefix='tests/isolated/'):
-    output = run_python(prefix + path).rstrip()
+def run_isolated(path, prefix='tests/isolated/', env=None):
+    output = run_python(prefix + path, env=env).rstrip()
     if output.startswith(b'skip'):
         parts = output.split(b':', 1)
         skip_args = []
         if len(parts) > 1:
             skip_args.append(parts[1])
         raise SkipTest(*skip_args)
-    assert output == b'pass', output
+    ok = output == b'pass'
+    if not ok:
+        sys.stderr.write('Isolated test {0} output:\n---\n{1}\n---\n'.format(path, output.decode()))
+    assert ok, 'Expected single line "pass" in stdout'
 
 
 certificate_file = os.path.join(os.path.dirname(__file__), 'test_server.crt')

tests/socket_test.py

@@ -1,3 +1,4 @@
+import eventlet
 from eventlet.green import socket
 
 
@@ -6,3 +7,25 @@ def test_create_connection_error():
         socket.create_connection(('192.0.2.1', 80), timeout=0.1)
     except (IOError, OSError):
         pass
+
+
+def test_recv_type():
+    # https://github.com/eventlet/eventlet/issues/245
+    # socket recv returning multiple data types
+    # For this test to work, client and server have to be in separate
+    # processes or OS threads. Just running two greenthreads gives
+    # false test pass.
+    threading = eventlet.patcher.original('threading')
+    addr = []
+
+    def server():
+        sock = eventlet.listen(('127.0.0.1', 0))
+        addr[:] = sock.getsockname()
+        eventlet.sleep(0.2)
+
+    server_thread = threading.Thread(target=server)
+    server_thread.start()
+    eventlet.sleep(0.1)
+    sock = eventlet.connect(tuple(addr))
+    s = sock.recv(1)
+    assert isinstance(s, bytes)