Support `Iterable`, `Iterator`, and `ListIterator` with `@EmptySource`

[sdavids]

@ParameterizedTest
@EmptySource
void foo(Iterable<String> ids) {
  // ... test some API expecting Iterable
}

@ParameterizedTest
@NullAndEmptySource
void foo(Iterable<String> ids) {
  // ... test some API expecting Iterable
}

Deliverables

• @EmptySource supports java.lang.Iterable
• @EmptySource supports java.util.Iterator
• @EmptySource supports java.util.ListIterator

Motive

https://github.com/google/guava/wiki/CollectionUtilitiesExplained#iterables

[sbrannen]

See also:

• Support JDK concrete types for List, Set and Map in @EmptySource / EmptyArgumentsProvider #2791

[sbrannen]

It should be relatively straightforward to implement this by creating a custom, internal Iterable implementation that simply delegates to java.util.Collections.emptyIterator().

We'll discuss it within the team.

[mpkorstanje]

While we are adding those we could add Collections.emptyIterator() and Collections.emptyListIterator() to complete the set.