Add support for partially ordered parameter set matching

[laloona]

Summary

PHPUnit currently provides:

• withParameterSetsInOrder() (strict ordering)
• withParameterSetsInAnyOrder() (no ordering constraints)

There is no way to express partial ordering, where some calls must occur at specific positions while others may occur in any order.

Proposal

Introduce: withParameterSetsInPartialOrder() - partially ordered arguments

$mock->expects($this->exactly(4))
    ->method('dispatch')
    ->withParameterSetsInPartialOrder(
        $this->fixed($a),
        [$b],
        [$c],
        $this->fixed($d),
    );

• fixed(...) parameter sets must match exactly at their declared position
• other parameter sets may match remaining positions in any order
• all parameter sets must be matched exactly once

This allows expressing common patterns such as:

• setup → arbitrary operations → cleanup
• fixed first/last calls with flexible middle

I am open to alternative API designs if there is a better way to express this.

[sebastianbergmann]

Interesting idea. I am not convinced this is really needed. Do you have a real-world use case you can share? Thank you!

[laloona]

Yes.

One real-world use case for me is an import process where multiple events may occur in arbitrary order, but a final PersistEvent must be dispatched last.

If that event is not last, the data are not persisted correctly.

withParameterSetsInOrder() is too strict for this because it would over-constrain the preceding events, while withParameterSetsInAnyOrder() is too permissive because it cannot enforce PersistEvent as the final call.

That is the kind of gap I had in mind.