Authentication documentation
One of the trickiest, and yet most important, areas of testing web sites is the security. Testing these schemes is one of the core goals of the SimpleTest web tester.
Basic HTTP authentication
If you fetch a page protected by basic authentication then rather than receiving content, you will instead get a 401 header. We can illustrate this with this test...
class AuthenticationTest extends WebTestCase {
function test401Header() {
$this->get('http://www.lastcraft.com/protected/');
$this->showHeaders();
}
}
This allows us to see the challenge header...
File test
class AuthenticationTest extends WebTestCase {
function test401Header() {
$this->get('http://www.lastcraft.com/protected/');
$this->assertAuthentication('Basic');
$this->assertResponse(401);
$this->assertRealm('SimpleTest basic authentication');
}
}
Any one of these tests would normally do on it's own depending
on the amount of detail you want to see.
One theme that runs through SimpleTest is the ability to use
SimpleExpectation objects wherever a simple
match is not enough.
If you want only an approximate match to the realm for
example, you can do this...
class AuthenticationTest extends WebTestCase {
function test401Header() {
$this->get('http://www.lastcraft.com/protected/');
$this->assertRealm(new PatternExpectation('/simpletest/i'));
}
}
Most of the time we are not interested in testing the
authentication itself, but want to get past it to test
the pages underneath.
As soon as the challenge has been issued we can reply with
an authentication response...
class AuthenticationTest extends WebTestCase {
function testCanAuthenticate() {
$this->get('http://www.lastcraft.com/protected/');
$this->authenticate('Me', 'Secret');
$this->assertTitle(...);
}
}
The username and password will now be sent with every
subsequent request to that directory and subdirectories.
You will have to authenticate again if you step outside
the authenticated directory, but SimpleTest is smart enough
to merge subdirectories into a common realm.
You can shortcut this step further by encoding the log in details straight into the URL...
class AuthenticationTest extends WebTestCase {
function testCanReadAuthenticatedPages() {
$this->get('http://Me:Secret@www.lastcraft.com/protected/');
$this->assertTitle(...);
}
}
If your username or password has special characters, then you
will have to URL encode them or the request will not be parsed
correctly.
Also this header will not be sent on subsequent requests if
you request a page with a fully qualified URL.
If you navigate with relative URLs though, the authentication
information will be preserved.
Only basic authentication is currently supported and this is only really secure in tandem with HTTPS connections. This is usually enough to protect test server from prying eyes, however. Digest authentication and NTLM authentication may be added in the future.
Cookies
Basic authentication doesn't give enough control over the user interface for web developers. More likely this functionality will be coded directly into the web architecture using cookies and complicated timeouts.
Starting with a simple log-in form...
Username:
Password:
]]>
Which looks like...
Let's suppose that in fetching this page a cookie has been set with a session ID. We are not going to fill the form in yet, just test that we are tracking the user. Here is the test...
class LogInTest extends WebTestCase {
function testSessionCookieSetBeforeForm() {
$this->get('http://www.my-site.com/login.php');
$this->assertCookie('SID');
}
}
All we are doing is confirming that the cookie is set.
As the value is likely to be rather cryptic it's not
really worth testing this with...
class LogInTest extends WebTestCase {
function testSessionCookieIsCorrectPattern() {
$this->get('http://www.my-site.com/login.php');
$this->assertCookie('SID', new PatternExpectation('/[a-f0-9]{32}/i'));
}
}
The rest of the test would be the same as any other form,
but we might want to confirm that we still have the same
cookie after log-in as before we entered.
We wouldn't want to lose track of this after all.
Here is a possible test for this...
class LogInTest extends WebTestCase {
...
function testSessionCookieSameAfterLogIn() {
$this->get('http://www.my-site.com/login.php');
$session = $this->getCookie('SID');
$this->setField('u', 'Me');
$this->setField('p', 'Secret');
$this->click('Log in');
$this->assertText('Welcome Me');
$this->assertCookie('SID', $session);
}
}
This confirms that the session identifier is maintained
afer log-in.
We could even attempt to spoof our own system by setting arbitrary cookies to gain access...
class LogInTest extends WebTestCase {
...
function testSessionCookieSameAfterLogIn() {
$this->get('http://www.my-site.com/login.php');
$this->setCookie('SID', 'Some other session');
$this->get('http://www.my-site.com/restricted.php');
$this->assertText('Access denied');
}
}
Is your site protected from this attack?
Browser sessions
If you are testing an authentication system a critical piece of behaviour is what happens when a user logs back in. We would like to simulate closing and reopening a browser...
class LogInTest extends WebTestCase {
...
function testLoseAuthenticationAfterBrowserClose() {
$this->get('http://www.my-site.com/login.php');
$this->setField('u', 'Me');
$this->setField('p', 'Secret');
$this->click('Log in');
$this->assertText('Welcome Me');
$this->restart();
$this->get('http://www.my-site.com/restricted.php');
$this->assertText('Access denied');
}
}
The WebTestCase::restart() method will
preserve cookies that have unexpired timeouts, but throw away
those that are temporary or expired.
You can optionally specify the time and date that the restart
happened.
Expiring cookies can be a problem. After all, if you have a cookie that expires after an hour, you don't want to stall the test for an hour while the cookie passes it's timeout.
To push the cookies over the hour limit you can age them before you restart the session...
class LogInTest extends WebTestCase {
...
function testLoseAuthenticationAfterOneHour() {
$this->get('http://www.my-site.com/login.php');
$this->setField('u', 'Me');
$this->setField('p', 'Secret');
$this->click('Log in');
$this->assertText('Welcome Me');
$this->ageCookies(3600);
$this->restart();
$this->get('http://www.my-site.com/restricted.php');
$this->assertText('Access denied');
}
}
After the restart it will appear that cookies are an
hour older and any that pass their expiry will have
disappeared.
