Fix unit test for verifying enforced expire date too far in the future

The test should fail if no exception was thrown, and no exception was
thrown due to a missing configuration parameter. However, the use of
"addToAssertionCount(1)" made the test pass even if no exception was
thrown and, therefore, to silently fail.

Now the missing configuration parameter was added and the test will fail
if the expected exception is not thrown.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>