public async Task Validate_ValidExternalActorId_ValidatesProperty()
    {
        // Arrange
        const string propertyName = nameof(UpdateActorCommand.ExternalActorId);

        var target  = new UpdateActorCommandRuleSet();
        var command = new UpdateActorCommand(_validUuid, Guid.NewGuid());

        // Act
        var result = await target.ValidateAsync(command).ConfigureAwait(false);

        // Assert
        Assert.True(result.IsValid);
        Assert.DoesNotContain(propertyName, result.Errors.Select(x => x.PropertyName));
    }
    public async Task Validate_InvalidActorId_ValidatesProperty()
    {
        // Arrange
        const string propertyName = nameof(UpdateActorCommand.ActorId);

        var target  = new UpdateActorCommandRuleSet();
        var command = new UpdateActorCommand(Guid.Empty, _validUuid);

        // Act
        var result = await target.ValidateAsync(command).ConfigureAwait(false);

        // Assert
        Assert.False(result.IsValid);
        Assert.Contains(propertyName, result.Errors.Select(x => x.PropertyName));
    }