add a functional online test for login ok/failure

tests/test_online_login.py

@@ -0,0 +1,28 @@
+import pytest
+import imaplib
+
+
+@pytest.fixture
+def conn():
+    return connect("c1.testrun.org")
+
+
+def login(conn, user, password):
+    print("trying to login", user, password)
+    conn.login(user, password)
+
+
+def connect(host):
+    print(f"connecting to {host}")
+    conn = imaplib.IMAP4_SSL(host)
+    return conn
+
+
+def test_login_ok(conn):
+    login(conn, "link2xt@c1.testrun.org", "Ahyei6ie")
+
+
+def test_login_fail(conn):
+    with pytest.raises(imaplib.IMAP4.error) as excinfo:
+        login(conn, "link2xt@c1.testrun.org", "qweqwe")
+    assert "AUTHENTICATIONFAILED" in str(excinfo)