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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NUnit.Framework;
namespace Xamarin.PropertyEditing.Tests
{
[TestFixture]
internal class AsyncValueTests
{
[Test]
public void ValueOnCompletion ()
{
var tcs = new TaskCompletionSource<string> ();
var asyncValue = new AsyncValue<string> (tcs.Task, scheduler: new SyncScheduler());
Assume.That (asyncValue.Value, Is.Null);
bool changed = false;
asyncValue.PropertyChanged += (sender, args) => {
if (args.PropertyName == nameof (AsyncValue<string>.Value))
changed = true;
};
const string value = "value";
tcs.SetResult (value);
Assert.That (asyncValue.Value, Is.EqualTo (value));
Assert.That (changed, Is.True, "PropertyChanged did not fire for Value");
}
[Test]
public void DefaultValue ()
{
var tcs = new TaskCompletionSource<bool> ();
var value = new AsyncValue<bool> (tcs.Task, defaultValue: true, scheduler: new SyncScheduler());
Assert.That (value.Value, Is.True);
}
[TestCase (true)]
[TestCase (false)]
public void ValueReplacesDefaultValue (bool value)
{
var tcs = new TaskCompletionSource<bool> ();
var asyncValue = new AsyncValue<bool> (tcs.Task, defaultValue: !value, scheduler: new SyncScheduler());
Assume.That (asyncValue.Value, Is.EqualTo (!value));
tcs.SetResult (value);
Assert.That (asyncValue.Value, Is.EqualTo (value));
}
[Test]
public void IsRunning ()
{
var tcs = new TaskCompletionSource<string> ();
var asyncValue = new AsyncValue<string> (tcs.Task, scheduler: new SyncScheduler());
Assume.That (asyncValue.Value, Is.Null);
Assert.That (asyncValue.IsRunning, Is.True);
bool changed = false;
asyncValue.PropertyChanged += (sender, args) => {
if (args.PropertyName == nameof (AsyncValue<string>.IsRunning))
changed = true;
};
const string value = "value";
tcs.SetResult (value);
Assume.That (asyncValue.Value, Is.EqualTo (value));
Assert.That (asyncValue.IsRunning, Is.False, "IsRunning did not flip to false");
Assert.That (changed, Is.True, "PropertyChanged did not fire for IsRunning");
}
[Test]
public void AsyncValueException ()
{
var tcs = new TaskCompletionSource<bool> ();
var asyncValue = new AsyncValue<bool> (tcs.Task, defaultValue: true, scheduler: new SyncScheduler());
Assume.That (asyncValue.Value, Is.True);
bool valueChanged = false, runningChanged = false;
asyncValue.PropertyChanged += (sender, args) => {
if (args.PropertyName == nameof (AsyncValue<string>.Value))
valueChanged = true;
else if (args.PropertyName == nameof (AsyncValue<string>.IsRunning))
runningChanged = true;
};
tcs.SetException (new Exception ());
Assert.That (asyncValue.Value, Is.True);
Assert.That (valueChanged, Is.False, "Value should not signal change when there's an exception");
Assert.That (asyncValue.IsRunning, Is.False);
Assert.That (runningChanged, Is.True);
}
}
internal class SyncScheduler
: TaskScheduler
{
protected override void QueueTask (Task task)
{
TryExecuteTaskInline (task, false);
}
protected override bool TryExecuteTaskInline (Task task, bool taskWasPreviouslyQueued)
{
return TryExecuteTask (task);
}
protected override IEnumerable<Task> GetScheduledTasks ()
{
return Enumerable.Empty<Task> ();
}
}
}
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