Question

I can’t understand how I can setup a parametrized test with spock for void methods.
This is my simple test case for a linked list:

@Unroll
def "should delete the element #key and set the list size to #listSize"(key, listSize) {
    given:
    list.insert(6)
    list.insert(12)
    list.insert(33)

    expect:
    def deletedKey = list.delete(key)
    list.size() == listSize

    where:
    key || listSize
    6   || 2
    12  || 2
    33  || 2
    99  || 3
}

The method delete() is a void method, but if I’m not getting explicitly a return value then the test is failing.

This is actually working:

expect:
def deletedKey = list.delete(key)
list.size() == listSize

while this doesn’t:

expect:
list.delete(key)
list.size() == listSize

The test report complains about a null

Condition not satisfied:

list.delete(key)
|    |      |
|    null   12
com.github.carlomicieli.dst.LinkedList@5c533a2

How can I manage this situation? I would like to test the results of deletion checking the list state after the deletion method has been called.

Thanks,
Carlo

Answer 1

Does it work if you use when and then rather than expect?

@Unroll
def "should delete the element #key and set the list size to #listSize"(key, listSize) {
    given:
    list.insert(6)
    list.insert(12)
    list.insert(33)

    when:
    list.delete(key)

    then:
    list.size() == listSize

    where:
    key || listSize
    6   || 2
    12  || 2
    33  || 2
    99  || 3
}