How do I install the Gpui Testing skill?

Run npx skillmds@latest add pinkpixel-dev-skills-collection-1/gpui-testing in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

What does the Gpui Testing skill do?

Testing GPUI applications and components. Use when writing tests, testing async operations, simulating user input, or debugging test failures. It is listed under Coding & Dev Tools on SkillMD.

Is Gpui Testing safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: makes network calls. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Gpui Testing?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Gpui Testing free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Gpui Testing?

pinkpixel-dev (@pinkpixel-dev-skills-collection-1) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Gpui Testing by pinkpixel-dev-skills-collection-1

Name: Gpui Testing
Rating: 4.2 (5 reviews)
Author: pinkpixel-dev

GPUI Testing

This skill covers testing patterns for GPUI applications.

Overview

GPUI provides testing utilities for:

TestAppContext: Test harness for GPUI apps
Async test execution: with run_until_parked()
User input simulation: clicks, key presses
Entity testing: Creating and interacting with test entities

Test Setup

Basic Test Structure

#[cfg(test)]
mod tests {
    use super::*;
    use gpui::*;

    #[gpui::test]
    async fn test_my_view(cx: &mut TestAppContext) {
        // Test code here
    }
}

Creating Test Entities

#[gpui::test]
async fn test_counter(cx: &mut TestAppContext) {
    let counter = cx.new(|_| Counter { count: 0 });
    
    assert_eq!(counter.read(cx).count, 0);
}

Async Testing

Using run_until_parked

#[gpui::test]
async fn test_async_operation(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    view.update(cx, |view, cx| {
        view.start_async_work(cx);
    });
    
    // Wait for all async work to complete
    cx.background_executor.run_until_parked();
    
    // Check results
    assert_eq!(view.read(cx).status, "Complete");
}

GPUI Timers in Tests

IMPORTANT: Use GPUI executor timers, not smol::Timer:

#[gpui::test]
async fn test_with_delay(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    // ✅ CORRECT - Use GPUI timer
    cx.background_executor.timer(Duration::from_secs(1)).await;
    
    // ❌ WRONG - Don't use smol::Timer
    // smol::Timer::after(Duration::from_secs(1)).await;
    
    cx.background_executor.run_until_parked();
}

Why: GPUI's scheduler tracks GPUI timers but not smol::Timer, which can cause "nothing left to run" errors in run_until_parked().

Testing Entity Updates

Update and Verify

#[gpui::test]
async fn test_increment(cx: &mut TestAppContext) {
    let counter = cx.new(|_| Counter { count: 0 });
    
    counter.update(cx, |counter, cx| {
        counter.increment(cx);
    });
    
    assert_eq!(counter.read(cx).count, 1);
}

Testing Notify

#[gpui::test]
async fn test_notify(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    let observed = Arc::new(AtomicBool::new(false));
    let observed_clone = observed.clone();
    
    cx.observe(&view, move |_view, _cx| {
        observed_clone.store(true, Ordering::SeqCst);
    });
    
    view.update(cx, |view, cx| {
        view.data = "changed".into();
        cx.notify();
    });
    
    assert!(observed.load(Ordering::SeqCst));
}

Testing Actions

Dispatching Actions

actions!(test, [TestAction]);

#[gpui::test]
async fn test_action_handling(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    // Simulate action dispatch
    view.update(cx, |view, cx| {
        view.handle_action(&TestAction, cx);
    });
    
    assert_eq!(view.read(cx).action_count, 1);
}

Testing Subscriptions

Event Emission

#[derive(Clone, Debug)]
enum MyEvent {
    ValueChanged(i32),
}

impl EventEmitter<MyEvent> for MyView {}

#[gpui::test]
async fn test_event_emission(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    let received_events = Arc::new(Mutex::new(Vec::new()));
    let events_clone = received_events.clone();
    
    cx.subscribe(&view, move |_this, _emitter, event, _cx| {
        events_clone.lock().unwrap().push(event.clone());
    });
    
    view.update(cx, |view, cx| {
        cx.emit(MyEvent::ValueChanged(42));
    });
    
    let events = received_events.lock().unwrap();
    assert_eq!(events.len(), 1);
}

Testing Async Operations

Background Task Completion

#[gpui::test]
async fn test_background_task(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    view.update(cx, |view, cx| {
        cx.spawn(async move |this, cx| {
            let result = cx.background_spawn(async {
                // Expensive computation
                42
            }).await;
            
            this.update(&mut *cx, |view, cx| {
                view.result = Some(result);
                cx.notify();
            })?;
            
            Ok(())
        }).detach();
    });
    
    // Wait for all async work
    cx.background_executor.run_until_parked();
    
    assert_eq!(view.read(cx).result, Some(42));
}

Testing Task Cancellation

#[gpui::test]
async fn test_task_cancellation(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    view.update(cx, |view, cx| {
        view.start_long_task(cx);
    });
    
    // Cancel task
    view.update(cx, |view, cx| {
        view.cancel_task();
    });
    
    cx.background_executor.run_until_parked();
    
    // Task should not have completed
    assert_eq!(view.read(cx).task_completed, false);
}

Assertions and Expectations

Entity State Assertions

#[gpui::test]
async fn test_state_changes(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    // Initial state
    assert_eq!(view.read(cx).count, 0);
    
    // After update
    view.update(cx, |view, cx| {
        view.count = 10;
        cx.notify();
    });
    
    assert_eq!(view.read(cx).count, 10);
}

Using assert Macros

#[gpui::test]
async fn test_with_assertions(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    view.update(cx, |view, cx| {
        view.process_data(vec![1, 2, 3], cx);
    });
    
    cx.background_executor.run_until_parked();
    
    let view_state = view.read(cx);
    assert!(view_state.is_processed);
    assert_eq!(view_state.items.len(), 3);
    assert!(view_state.error.is_none());
}

Testing Patterns

Setup and Teardown

#[gpui::test]
async fn test_with_setup(cx: &mut TestAppContext) {
    // Setup
    let state = cx.new(|_| AppState::default());
    cx.set_global(state.clone());
    
    // Test
    let view = cx.new(|_| MyView::new());
    view.update(cx, |view, cx| {
        view.use_global_state(cx);
    });
    
    // Assertions
    assert!(view.read(cx).has_state);
    
    // Teardown is automatic when test ends
}

Testing Error Cases

#[gpui::test]
async fn test_error_handling(cx: &mut TestAppContext) {
    let view = cx.new(|_| MyView::new());
    
    view.update(cx, |view, cx| {
        cx.spawn(async move |this, cx| {
            // Simulate error
            let result: Result<(), anyhow::Error> = Err(anyhow::anyhow!("Test error"));
            
            this.update(&mut *cx, |view, cx| {
                view.error = result.err().map(|e| e.to_string());
                cx.notify();
            })?;
            
            Ok(())
        }).detach();
    });
    
    cx.background_executor.run_until_parked();
    
    assert!(view.read(cx).error.is_some());
}

Best Practices

Use #[gpui::test] attribute: Required for GPUI tests
Use GPUI timers: cx.background_executor.timer() instead of smol::Timer
Call run_until_parked(): For async operations
Test one thing at a time: Keep tests focused
Use descriptive names: Test names should describe what they test
Clean up resources: Though GPUI handles most cleanup automatically

Common Mistakes

Mistake	Problem	Solution
Using `smol::Timer`	"Nothing left to run"	Use `cx.background_executor.timer()`
Not calling `run_until_parked()`	Async work doesn't complete	Call before assertions
Forgetting `#[gpui::test]`	Test doesn't run properly	Use `#[gpui::test]` attribute
Not handling errors in async	Test failures unclear	Propagate errors with `?`
Testing too much at once	Hard to debug failures	Split into smaller tests

Example Test Suite

#[cfg(test)]
mod tests {
    use super::*;
    use gpui::*;
    use std::sync::{Arc, atomic::{AtomicBool, Ordering}};

    #[gpui::test]
    async fn test_counter_initialization(cx: &mut TestAppContext) {
        let counter = cx.new(|_| Counter { count: 0 });
        assert_eq!(counter.read(cx).count, 0);
    }

    #[gpui::test]
    async fn test_counter_increment(cx: &mut TestAppContext) {
        let counter = cx.new(|_| Counter { count: 0 });
        
        counter.update(cx, |counter, cx| {
            counter.increment(cx);
        });
        
        assert_eq!(counter.read(cx).count, 1);
    }

    #[gpui::test]
    async fn test_counter_async_increment(cx: &mut TestAppContext) {
        let counter = cx.new(|_| Counter { count: 0 });
        
        counter.update(cx, |counter, cx| {
            cx.spawn(async move |this, cx| {
                // Simulate async delay
                cx.background_executor.timer(Duration::from_millis(100)).await;
                
                this.update(&mut *cx, |counter, cx| {
                    counter.count += 1;
                    cx.notify();
                })?;
                
                Ok(())
            }).detach();
        });
        
        cx.background_executor.run_until_parked();
        assert_eq!(counter.read(cx).count, 1);
    }

    #[gpui::test]
    async fn test_counter_notify(cx: &mut TestAppContext) {
        let counter = cx.new(|_| Counter { count: 0 });
        let notified = Arc::new(AtomicBool::new(false));
        let notified_clone = notified.clone();
        
        cx.observe(&counter, move |_counter, _cx| {
            notified_clone.store(true, Ordering::SeqCst);
        });
        
        counter.update(cx, |counter, cx| {
            counter.count = 5;
            cx.notify();
        });
        
        assert!(notified.load(Ordering::SeqCst));
    }
}

Summary

Use #[gpui::test] for GPUI tests
Use cx.background_executor.timer() for delays
Call run_until_parked() to complete async work
Test entity updates with .update() and .read()
Use Arc and Mutex for tracking callbacks
Avoid smol::Timer in tests

Gpui Testing

File contents

GPUI Testing

Overview

Test Setup

Basic Test Structure

Creating Test Entities

Async Testing

Using run_until_parked

GPUI Timers in Tests

Testing Entity Updates

Update and Verify

Testing Notify

Testing Actions

Dispatching Actions

Testing Subscriptions

Event Emission

Testing Async Operations

Background Task Completion

Testing Task Cancellation

Assertions and Expectations

Entity State Assertions

Using assert Macros

Testing Patterns

Setup and Teardown

Testing Error Cases

Best Practices

Common Mistakes

Example Test Suite

Summary

References

Frequently asked questions

Gpui Testing

File contents

GPUI Testing

Overview

Test Setup

Basic Test Structure

Creating Test Entities

Async Testing

Using run_until_parked

GPUI Timers in Tests

Testing Entity Updates

Update and Verify

Testing Notify

Testing Actions

Dispatching Actions

Testing Subscriptions

Event Emission

Testing Async Operations

Background Task Completion

Testing Task Cancellation

Assertions and Expectations

Entity State Assertions

Using assert Macros

Testing Patterns

Setup and Teardown

Testing Error Cases

Best Practices

Common Mistakes

Example Test Suite

Summary

References

Related skills

Frequently asked questions

How do I install the Gpui Testing skill?

What does the Gpui Testing skill do?

Is Gpui Testing safe to use?

Which AI agents work with Gpui Testing?

Is Gpui Testing free to use?

Who published Gpui Testing?