extractSubject
fun <T> Expect<T>.extractSubject(failureDescription: String? = null, assertionCreator: Expect<T>.(T) -> Unit): Expect<T>(source)
Extracts the subject of this Expect in case it is defined and passes it to the given assertionCreator or adds a failing assertion to this Expect in case the subject is absent (e.g. due to a previous extraction failure).
Return
an Expect for the subject of this expectation.
Since
1.2.0
Parameters
failureDescription
The description used in case the subject is absent - if null is given, then the default failure description is used
assertionCreator
The assertion-creator lambda which is responsible to create and append at least 1 assertion to this Expect.
Samples
val persons = dataGenerator.getRandomPersonsWithChildren()
expect(persons).toHaveElementsAndAll {
extractSubject { person ->
feature { f(it::children) }.notToHaveElementsOrAll {
because("person should at least be 16 years older than its children") {
feature { f(it::age) }.toBeLessThan(person.age - 16)
}
}
}
}// imagine the data generator should not return an empty list
val persons = dataGenerator.getRandomPersonsHasABugReturnsEmptyList()
fails { // because persons is empty
expect(persons).toHaveElementsAndAll { // fails
// hence the sub-expectations within extractSubject cannot be evaluated
// and instead we show the custom failure description
extractSubject("no person defined, cannot extract subject") { person ->
feature { f(it::children) }.notToHaveElementsOrAll {
because("person should at least be 16 years older than its children") {
feature { f(it::age) }.toBeLessThan(person.age - 16)
}
}
}
}
}