file-transfer: writing tests and ensuring that all is going well

file_transfer/send_file.py

@@ -1,11 +1,6 @@
-if __name__ == "__main__":
-    import socket  # Import socket module
-
-    ONE_CONNECTION_ONLY = (
-        True  # Set this to False if you wish to continuously accept connections
-    )
+def send_file(filename: str = "mytext.txt", testing: bool = False) -> None:
+    import socket
 
-    filename = "mytext.txt"
     port = 12312  # Reserve a port for your service.
     sock = socket.socket()  # Create a socket object
     host = socket.gethostname()  # Get local machine name
@@ -29,10 +24,12 @@
 
         print("Done sending")
         conn.close()
-        if (
-            ONE_CONNECTION_ONLY
-        ):  # This is to make sure that the program doesn't hang while testing
+        if testing:  # Allow the test to complete
             break
 
     sock.shutdown(1)
     sock.close()
+
+
+if __name__ == "__main__":
+    send_file()

file_transfer/tests/test_send_file.py

@@ -0,0 +1,32 @@
+from unittest.mock import patch, Mock
+
+
+from file_transfer.send_file import send_file
+
+
+@patch("socket.socket")
+@patch("builtins.open")
+def test_send_file_running_as_expected(file, sock):
+    # ===== initialization =====
+    conn = Mock()
+    sock.return_value.accept.return_value = conn, Mock()
+    f = iter([1, None])
+    file.return_value.__enter__.return_value.read.side_effect = lambda _: next(f)
+
+    # ===== invoke =====
+    send_file(filename="mytext.txt", testing=True)
+
+    # ===== ensurance =====
+    sock.assert_called_once()
+    sock.return_value.bind.assert_called_once()
+    sock.return_value.listen.assert_called_once()
+    sock.return_value.accept.assert_called_once()
+    conn.recv.assert_called_once()
+
+    file.return_value.__enter__.assert_called_once()
+    file.return_value.__enter__.return_value.read.assert_called()
+
+    conn.send.assert_called_once()
+    conn.close.assert_called_once()
+    sock.return_value.shutdown.assert_called_once()
+    sock.return_value.close.assert_called_once()

requirements.txt

@@ -3,6 +3,7 @@ black
 fake_useragent
 flake8
 keras
+lxml
 matplotlib
 mypy
 numpy