Added a session id.

tests/step_defs/test_session.py

@@ -0,0 +1,25 @@
+"""tests for server sessions."""
+
+from pytest_bdd import given, scenarios, then, when
+
+scenarios("../features/session.feature")
+
+
+@given("a running server")
+def start_server(server):
+    """Make a running server."""
+    server.set_safe_port()
+    server.start()
+
+
+@when("the home page is accessed")
+def access_home_page(server, page):
+    """Access the home page."""
+    url = f"http://{server.base_url}/"
+    page.request_url(url)
+
+
+@then("there is a session id")
+def confirm_session(page):
+    """Confirm session id exists."""
+    assert page.get_header("set-cookie")