some very basic tests for the iostream.

tests/test_iostream.py

@@ -0,0 +1,62 @@
+from psyclone import iostream
+import socket
+
+def pytest_funcarg__server_socket(request):
+    '''Funcarg to create a UDP socket that can be communicated with. Why UDP
+    when the httpserver we'll be testing is tcp?  So we don't have to set up an
+    entire socket server using listen and accept. We're testing iostream now,
+    not httpserver.
+    
+    A better solution is probably to create a mock object.'''
+    read_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    read_socket.bind(("localhost", 9562))
+    request.addfinalizer(lambda: read_socket.close())
+    return read_socket
+
+def pytest_funcarg__bound_socket(request):
+    '''Funcarg to create a socket that communicates with the socket above.'''
+    write_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    write_socket.connect(("localhost", 9562))
+    request.addfinalizer(lambda: write_socket.close())
+    return write_socket
+
+def test_read_until(IOloop, server_socket, bound_socket):
+    stream = iostream.IOStream(server_socket, IOloop)
+    class checker:
+        pass
+    def onread(data):
+        checker.data = data
+        IOloop.stop()
+    def send_val():
+        bound_socket.send(b"This is a line.\na second line")
+    stream.read_until('\n', onread)
+    IOloop.add_callback(send_val)
+    IOloop.start()
+    assert checker.data == "This is a line.\n"
+
+def test_read_bytes(IOloop, server_socket, bound_socket):
+    stream = iostream.IOStream(server_socket, IOloop)
+    class checker:
+        pass
+    def onread(data):
+        checker.data = data
+        IOloop.stop()
+    def send_val():
+        bound_socket.send(b"This is a line.\na second line")
+    stream.read_bytes(5, onread)
+    IOloop.add_callback(send_val)
+    IOloop.start()
+    assert checker.data == 'This '
+
+def test_write(IOloop, server_socket, bound_socket):
+    rcv_stream = iostream.IOStream(server_socket, IOloop)
+    send_stream = iostream.IOStream(bound_socket, IOloop)
+    class checker:
+        pass
+    def onread(data):
+        checker.data = data
+        IOloop.stop()
+    send_stream.write(b'This is a line\n')
+    rcv_stream.read_until('\n', onread)
+    IOloop.start()
+    assert checker.data == 'This is a line\n'