public async Task Flatten_ReturnsATask()
{
var pipeline = CreatePipeline.With(() => 5);
var task = pipeline.Flatten();
Assert.Equal(5, await task);
}
public async Task Select_ComposesTaskReturningMethod()
{
async Task <int> AddFour(int number) => await(number + 4).AsTask();
var pipeline = CreatePipeline.With(() => 5).Select(AddFour);
var task = pipeline.Flatten();
Assert.Equal(9, await task);
}
public async Task SelectMany_ComposesPipeReturningMethod()
{
var initialPipeline = CreatePipeline.With(() => 5);
var resultingPipeline = initialPipeline.SelectMany(five => CreatePipeline.With(() => five + 4));
var task = resultingPipeline.Flatten();
Assert.Equal(9, await task);
}
public async Task SelectMany_AllowsLinqSyntacticSugarForMonadicComposition()
{
var firstPipeline = CreatePipeline.With(() => 5);
var secondPipeline = CreatePipeline.With(() => 6);
var thirdPipeline = CreatePipeline.With(() => 9);
var resultingPipeline = from firstValue in firstPipeline
from secondValue in secondPipeline
from thirdValue in thirdPipeline
select firstValue + secondValue + thirdValue;
var task = resultingPipeline.Flatten();
Assert.Equal(20, await task);
}