A testing library for Blazor components. Get started testing Blazor components at bunit.egilhansen.com/docs/getting-started/
Thanks for the feedback Egil. I was thinking about creating some BDD business test scenarios such as "When I want to pay out approved insurance claims, I first click on 'Pending Claims' in the application dashboard, then select the first approved claim listed then on the summary claim screen click the 'Issue Payment' button.". In a typical LOB Blazor app that scenario might traverse across 3 top level routable components. I gather from your first response that the Blazor navigation manager and location changed events are not hooked into the scope of a CUT?
But if you want to use navigation manager, you simply register one through the Services collection
I havent tried writing tests where the default blazor router is included, but that might work. you are certainly the first to ask though :)
I recommend starting with just testing individual components. Thats where bUnit execelles. But I am very interested in learning more about your scenario. Feel free to create a QA in the https://github.com/egil/bUnit/discussions. Its a much better place to share code samples and keep track of a discussion.
Is it possible to create a bunit test that checks for an expected UI update that should occur in response to a data update applied to a Fluxor state store? In this scenario I assume my Blazor component under test is bound to data in the Fluxor state store created as part of the test.
I dont see a problem with that. The only challange might be that the data arrives asynchronously, and thus you might need to use
cut.WaitForAssertion(() => /* assertion goes here */) since the test code runs in one thread and the component and renderer in another, to avoid deadlocks.
How is the Fluxor state store made available to the component?
According to the Fluxor docs the state store is injected as a private property. Yes I was anticipating the need to use cut.WaitForAssertion after reading your replies 13th Nov to @forex.ray.v1_gitlab and how to handle the delay when a unit test makes a live async remote request for data. Your recent presentation with Microsoft available on YouTube was very helpful particularly that bunit architectural slide, now I can picture where the threads run during a unit test.
but glad it helped
Is it injected with DI or is it a cascading value?
Eitherway, you will want a way to control that in your tests. If you can set the data in the store before your render your component, then its likely that the renderer will render the component synchronously and you wont need to use waitforxxx
control it, as have a way to set data in it.
Anyway, when you get it working, do post a sample in the discussions forum under the show and tell category. Will likely be very useful to others.
[Inject]
private IState<CounterState> CounterState { get; set; } https://github.com/mrpmorris/Fluxor/blob/master/Tutorials/02-Blazor/02A-StateActionsReducersTutorial/README.md
Anyway, it does seem like you can just mock or even better, create fake of
IState, and then in your test, write Services.AddSingleton<IState<CounterState>>(new FakeState(....))
PS: @camelCaseSharp -> https://gitter.im/mrpmorris/fluxor
If you are interested
Hi Egil. I'm writing some tests and running into an issue with context menus. Our solution is using a nuget package (Blazor.ContextMenu v.1.8.0) for context menus in our app. It seems like they may be using the HTML 'oncontextmenu' event rather than the blazor '@oncontextmenu' event, would that make it so that the Element.ContextMenu() call in BUnit can't find the event?
its like they have a c# method that is javascript invocable. If thats the case, you can simply invoke that method yourself.
It looks like they are calling a method in their component called ShowMenu and HideMenu: https://github.com/stavroskasidis/BlazorContextMenu/blob/master/BlazorContextMenu/wwwroot/blazorContextMenu.js#L177
But actually, you might jus be able to get one of these out of the services collection and use that: https://github.com/stavroskasidis/BlazorContextMenu/blob/master/BlazorContextMenu/Services/BlazorContextMenuService.cs#L10
It has hide and show menu methods
That's a good find on the service. It doesn't seem like making the call on the service actually changes my html at this point. Should I be able to call instance methods on their component from my code? It doesn't seem like the ShowMenu and HideMenu methods are publicly available for me to call something like cut.ShowMenu() in my test code.
Otherwise, you can always try to find components in the component tree by using
cut.FindComponent<TypeOfComponent>()
Then you can do e.g.
var menu = cut.FindComponent<ContextMenu>() and then inspect menu.Instanceto see what options you have on the component.
So some times I really want to kick myself for not thinking of something earlier. This is one of those times. This morning I realized that the inline render fragment syntax in razor has the potential for much better razor based tests.
Have small spike, where this is possible:
@inherits TestComponentBase2
@code
{
[Fact]
public void Test1()
{
var cut = RenderFragment(@<div>hello world</div>);
cut.MarkupMatches(@<div>hello world</div>);
}
[Fact]
public void Test2()
{
var cut = RenderComponent<Counter>(@<Counter DarkMode="true">
</Counter>);
Assert.True(cut.Instance.DarkMode);
}
[Fact]
public void Counter_Increments_When_Button_Is_Clicked()
{
var cut = RenderFragment(@<Counter DarkMode="true" />);
cut.Find("button").Click();
cut.Find("p").MarkupMatches(@<p>Current count: 1</p>);
}
}What do you guys think?
I like it a lot
If I want to test a component that has phases. It returns state one and then after it finishes loading returns another state. How can I tell the CUT to rerender after I change the MOQ so it will return the second state? Basically, I want to do the first MarkupMatches(Frag1), change the MOQ so will return the second state, then "somehow tell component to rerender" then do Second MarkupMatches(Frag2)?
Otherwise, how does it work in a real app?
Anyway, to answer your question, you can always call
cut.Render() or cut.SetParametersAndRender(...) if you need to pass new parameters.
Here is the relevant doc: https://bunit.egilhansen.com/docs/interaction/trigger-renders.html
That will return a IRenderedComponent<TComponent>
Running into some behavior I don't understand. I have a Page component. The Page has a Form component. The Form has controls on it. I am asserting on the contents of the form. I have one particular test where the contents of the form controls are not what I'm expecting. When I examine the markup of the Page, the contents are exactly what I expect to see. But when I examine the contents of the form IRenderFragment, retrieved with _RenderedPage.FindComponent<Form>(), they are different, containing values that were set previously in the test but that were subsequently cleared out.
What could be going on here? Is there some need to refresh something? Is there some race condition?
Hi @demonsweatlive, not sure without seeing any code, but it could be a race condition. For that, you might need this: https://bunit.egilhansen.com/docs/verification/async-assertion.html
There is also this method: https://bunit.egilhansen.com/docs/interaction/awaiting-async-state.html