lib/Assertion.php
private function expect($target, Constraint $constraint): self {
    assertThat($target, $this->hasFlag('negate') ? logicalNot($constraint) : $constraint, $this->message);
    return $this;
  }
private function expect($target, Constraint $constraint): self {
    assertThat($target, $this->hasFlag('negate') ? logicalNot($constraint) : $constraint, $this->message);
    return $this;
  }
Asserts that the specified target matches the specified constraint.
@param mixed $target The target to check.
@param Constraint $constraint The constraint to match.
@return self This instance.