As Jeff Schnitzer says in the link provided by Michael Osofsky:
In your tests you should have some notion of a 'request' even if it is just conceptual. If "each test is a request by itself", then you can use @Before/@After in conjunction with ObjectifyService.begin() to demarcate the requests. However, this is probably not actually how your tests work - it isn't how my tests work.
He then goes on to say:
This would be prettier with JDK8 closures but the idea is straightforward - you're wrapping some unit of work in a context which represents a request. It would probably be smart to add even more context like authentication in that wrapper too.
I came up with the following implementation of his idea. With the solution below, you can ensure each call to a servlet handler gets a fresh Objectify session while still making your servlet handler calls in a single line of code. It also decouples your tests from explicitly worrying about Objectify, and allows you to add additional non-Objectify context around your servlet handlers.
My solution below works with Objectify 5.1.22. I tried using Objectify 6+, but I had problems that seem to be related to this.
First, define a custom Supplier that is able to capture the exceptions thrown by a servlet handler.
@FunctionalInterface
public interface ServletSupplier<T> {
T get()
throws ServletException, IOException;
}
Next, define a wrapper method that accepts your new custom Supplier as an input, and wrap the call to ServletSupplier.get() in a try-with-resources block that calls ObjectifyService.begin(). You must also register your entity classes before calling ServletSupplier.get().
public <T> T runInServletContext(ServletSupplier<T> servletMethod)
throws ServletException, IOException {
try (Closeable session = ObjectifyService.begin()) {
ObjectifyService.register(MyObj.class);
return servletMethod.get();
}
}
Finally, anywhere in your tests that you call the servlet handler you should do so using the wrapper method.
MyObj myObjPost = runInServletContext(() -> getServlet().doPost(request, response));
// Assert results of doPost call.
MyObj myObjGet = runInServletContext(() -> getServlet().doGet(request, response));
// Assert results of doGet call.
