addition: Bus\HasHandler Laravel constraint

[remipelhate]

Instead of having to check whether a handler is mapped using the facade directly:

$this->assertTrue(Bus::hasCommandHandler($message), "Missing handler for $messageClassFQN.");
$this->assertInstanceOf($useCaseClassFQN, Bus::getCommandHandler($message));

This new constraint encapsulates the logic and adds clear failure messages:

$this->assertThat($messageClassFCN, new HasHandler(useCaseClassFQN));

When the assertion fails, it will display one of the following failure messages:

Failed asserting that 'App\Some\Command' has handler.

* App\Some\Command has no handler mapped to it.

Failed asserting that 'App\Some\Command' has handler.

* App\Some\Command has a different handler mapped to it.

[fowbi]

👌🏻