I’ve got an application that only allows you to visit a url once (doing the same request again takes you elsewhere).

For example, imagine a wizard (or a purchase flow), something like this:

Step 1 > Step 2 > Step 3 > Step 4

...where between each step, the user POSTs a form and gets redirected to the next page using a standard Post/Redirect/Get flow.

...and the system is built so that going back/forward unexpectedly in the flow should take me to step 1.

For example:

• browser back button should take me to step 1
• browser back + forward button should take me to step 1

When I’m using BrowserKit to write a test for my application, it doesn't seem to do the same thing as my browser does.

This is how my regular browser (Chrome/Firefox) behaves (with HTTP requests in parentheses):

1. I visit the first page (GET /wizard-view-step-1)
2. I submit my choices (POST /wizard-complete-step-1)
3. I get redirected to the next page (GET /wizard-view-step-2)
4. I submit my choices (POST /wizard-complete-step-2)
5. I get redirected to the next page (GET /wizard-view-step-3)
6. I click my browser's back button (GET /wizard-view-step-2) <-- notice the skipping of the previous POST (no 4 above) and going directly to the last GET request (no 3 above), as per the Post/Redirect/Get pattern.
7. I get redirected to the first page (GET /wizard-view-step-1)
8. I click my browser's forward button (GET /wizard-view-step-3) <-- notice that my browser still remembers the page I've "already been to in the future" and takes me there.
9. I get redirected to the first page (GET /wizard-view-step-1)

...however...

When I do this with BrowserKit, there are 2 major differences compared to my regular graphical browser:

A) History->back() doesn't follow "PRG" (Post/Redirect/Get) flows correctly. It only steps backwards 1 step in my history, not skipping the POST requests that returned a redirect (HTTP status 3xx).

B) Being redirected differently when going back clears "future history". In BrowserKit (assuming that I manually skip the POST requests), when I go back (no 6 above), get redirected (no 7) and then try to go forward again I get a \LogicException with You are already on the last page.

Here's a simplified unit test (for BrowserKit\History) to illustrate "B" above (assuming we're keeping PRG flows out of the equation for now):

    public function testBackAndForward()
    {
        $history = new History();

        $history->add(new Request('http://www.example.com/wizard-view-step-1', 'get'));
        $history->add(new Request('http://www.example2a.com/wizard-view-step-2', 'get'));
        $history->add(new Request('http://www.example2a.com/wizard-view-step-3', 'get'));

        $history->back();

        $history->add(new Request('http://www.example.com/wizard-view-step-1', 'get'));

        $history->forward();

        $this->assertSame(
            'http://www.example.com/wizard-view-step-3', 
            $history->current()->getUri(), 
            '->forward() returns the next request in the history'
        );
    }