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Dioxus 0.4.3CookbookTesting
You are currently viewing the docs for Dioxus 0.4.3 which is no longer maintained.

Testing

When building application or libraries with Dioxus, you may want to include some tests to check the behavior of parts of your application. This guide will teach you how to test different parts of your Dioxus application.

Component Testing

You can use a combination of pretty-assertions and dioxus-ssr to check that two snippets of rsx are equal:

src/component_test.rs
use futures::FutureExt;
use std::{cell::RefCell, sync::Arc};

use dioxus::prelude::*;

#[test]
fn test() {
    assert_rsx_eq(
        rsx! {
            div {
                "Hello world"
            }
            div {
                "Hello world"
            }
        },
        rsx! {
            for _ in 0..2 {
                div {
                    "Hello world"
                }
            }
        },
    )
}

fn assert_rsx_eq(first: LazyNodes<'static, 'static>, second: LazyNodes<'static, 'static>) {
    let first = dioxus_ssr::render_lazy(first);
    let second = dioxus_ssr::render_lazy(second);
    pretty_assertions::assert_str_eq!(first, second);
}

Hook Testing

When creating libraries around Dioxus, it can be helpful to make tests for your custom hooks.

Dioxus does not currently have a full hook testing library, but you can build a bespoke testing framework by manually driving the virtual dom.

src/hook_test.rs
use futures::FutureExt;
use std::{cell::RefCell, sync::Arc};

use dioxus::prelude::*;

#[test]
fn test() {
    test_hook(
        |cx| use_ref(cx, || 0).clone(),
        |value, mut proxy| match proxy.generation {
            0 => {
                value.set(1);
            }
            1 => {
                assert_eq!(*value.read(), 1);
                value.set(2);
            }
            2 => {
                proxy.rerun();
            }
            3 => {}
            _ => todo!(),
        },
        |proxy| assert_eq!(proxy.generation, 4),
    );
}

fn test_hook<V: 'static>(
    initialize: impl FnMut(&ScopeState) -> V + 'static,
    check: impl FnMut(V, MockProxy) + 'static,
    mut final_check: impl FnMut(MockProxy) + 'static,
) {
    #[derive(Props)]
    struct MockAppComponent<
        I: FnMut(&ScopeState) -> V + 'static,
        C: FnMut(V, MockProxy) + 'static,
        V,
    > {
        hook: RefCell<I>,
        check: RefCell<C>,
    }

    impl<I: FnMut(&ScopeState) -> V, C: FnMut(V, MockProxy), V> PartialEq
        for MockAppComponent<I, C, V>
    {
        fn eq(&self, _: &Self) -> bool {
            true
        }
    }

    fn mock_app<I: FnMut(&ScopeState) -> V, C: FnMut(V, MockProxy), V>(
        cx: Scope<MockAppComponent<I, C, V>>,
    ) -> Element {
        let value = cx.props.hook.borrow_mut()(cx);

        cx.props.check.borrow_mut()(value, MockProxy::new(cx));

        render! {
            div {}
        }
    }

    let mut vdom = VirtualDom::new_with_props(
        mock_app,
        MockAppComponent {
            hook: RefCell::new(initialize),
            check: RefCell::new(check),
        },
    );

    let _ = vdom.rebuild();

    while vdom.wait_for_work().now_or_never().is_some() {
        let _ = vdom.render_immediate();
    }

    final_check(MockProxy::new(vdom.base_scope()));
}

struct MockProxy {
    rerender: Arc<dyn Fn()>,
    pub generation: usize,
}

impl MockProxy {
    fn new(scope: &ScopeState) -> Self {
        let generation = scope.generation();
        let rerender = scope.schedule_update();

        Self {
            rerender,
            generation,
        }
    }

    pub fn rerun(&mut self) {
        (self.rerender)();
    }
}

End to End Testing

You can use Playwright to create end to end tests for your dioxus application.

In your playwright.config.js, you will need to run cargo run or dx serve instead of the default build command. Here is a snippet from the end to end web example:

//...
webServer: [
    {
        cwd: path.join(process.cwd(), 'playwright-tests', 'web'),
        command: 'dx serve',
        port: 8080,
        timeout: 10 * 60 * 1000,
        reuseExistingServer: !process.env.CI,
        stdout: "pipe",
    },
],
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