aether_core/testing/
utils.rs

1use std::collections::BTreeMap;
2use std::sync::{Arc, Mutex};
3use std::time::Duration;
4use tokio::sync::{Notify, mpsc};
5
6use crate::context::CompactionConfig;
7use crate::core::{AgentError, Prompt, RetryConfig, agent};
8use crate::events::{
9    AgentCommand, AgentEvent, AgentObserver, Command, ContextEvent, ToolEvent, TurnEvent, UserCommand,
10};
11use crate::mcp::mcp;
12use crate::testing::{AgentTrace, FakeAgentObserver, FakeMcpServer, McpBuilderTestExt};
13use llm::{ChatMessage, Context, LlmError, LlmModel, LlmResponse, ModelSettings, StreamingModelProvider};
14
15use llm::testing::FakeLlmProvider;
16
17pub async fn drain_until(
18    receiver: &mut mpsc::Receiver<AgentEvent>,
19    predicate: impl Fn(&AgentEvent) -> bool,
20) -> Vec<AgentEvent> {
21    let mut events = Vec::new();
22    while let Some(event) = receiver.recv().await {
23        let matched = predicate(&event);
24        events.push(event);
25        if matched {
26            return events;
27        }
28    }
29    panic!("agent event channel closed before predicate matched");
30}
31
32pub fn content_events(events: Vec<AgentEvent>) -> Vec<AgentEvent> {
33    events
34        .into_iter()
35        .filter(|event| {
36            !matches!(
37                event,
38                AgentEvent::Turn(
39                    TurnEvent::Started { .. } | TurnEvent::LlmCallStarted { .. } | TurnEvent::LlmCallEnded { .. }
40                ) | AgentEvent::Tool(ToolEvent::ExecutionStarted { .. } | ToolEvent::DefinitionsUpdated { .. })
41            )
42        })
43        .collect()
44}
45
46pub fn mcp_instructions(entries: &[(&str, &str)]) -> BTreeMap<String, String> {
47    entries.iter().map(|(k, v)| ((*k).to_string(), (*v).to_string())).collect()
48}
49
50/// Millisecond-scale retry delays so retry tests run fast under virtual time.
51pub fn fast_retry(max_attempts: u32) -> RetryConfig {
52    RetryConfig { max_attempts, base_delay: Duration::from_millis(1), max_delay: Duration::from_millis(5) }
53}
54
55pub fn test_agent() -> TestAgentBuilder {
56    TestAgentBuilder::new()
57}
58
59/// An ordered interaction with a test agent.
60pub enum TestAgentStep {
61    Send(Command),
62    WaitFor(Box<dyn Fn(&AgentEvent) -> bool + Send>),
63    /// Run an arbitrary side effect (e.g. releasing a paused LLM stream) between steps.
64    Perform(Box<dyn FnOnce() + Send>),
65}
66
67impl TestAgentStep {
68    pub fn send(command: Command) -> Self {
69        Self::Send(command)
70    }
71
72    pub fn user_text(text: impl Into<String>) -> Self {
73        Self::send(Command::text(text))
74    }
75
76    pub fn cancel() -> Self {
77        Self::send(Command::UserCommand(UserCommand::Cancel))
78    }
79
80    pub fn switch_model(provider: impl StreamingModelProvider + 'static) -> Self {
81        Self::send(Command::AgentCommand(AgentCommand::SwitchModel(Box::new(provider))))
82    }
83
84    pub fn replace_conversation(messages: Vec<ChatMessage>) -> Self {
85        Self::send(Command::AgentCommand(AgentCommand::ReplaceConversation(messages)))
86    }
87
88    pub fn perform(action: impl FnOnce() + Send + 'static) -> Self {
89        Self::Perform(Box::new(action))
90    }
91
92    pub fn wait_for(predicate: impl Fn(&AgentEvent) -> bool + Send + 'static) -> Self {
93        Self::WaitFor(Box::new(predicate))
94    }
95
96    pub fn wait_for_turn_end() -> Self {
97        Self::wait_for(|event| matches!(event, AgentEvent::Turn(TurnEvent::Ended { .. })))
98    }
99
100    pub fn wait_for_compaction_start() -> Self {
101        Self::wait_for(|event| matches!(event, AgentEvent::Context(ContextEvent::CompactionStarted { .. })))
102    }
103
104    pub fn wait_for_retry(attempt: u32) -> Self {
105        Self::wait_for(
106            move |event| matches!(event, AgentEvent::Turn(TurnEvent::RetryScheduled { attempt: actual, .. }) if *actual == attempt),
107        )
108    }
109}
110
111/// A fluent sequence of commands and synchronization points for a test agent.
112#[derive(Default)]
113pub struct TestScenario {
114    steps: Vec<TestAgentStep>,
115}
116
117impl TestScenario {
118    pub fn new() -> Self {
119        Self::default()
120    }
121
122    pub fn send(mut self, command: Command) -> Self {
123        self.steps.push(TestAgentStep::send(command));
124        self
125    }
126
127    pub fn user_text(mut self, text: impl Into<String>) -> Self {
128        self.steps.push(TestAgentStep::user_text(text));
129        self
130    }
131
132    pub fn cancel(mut self) -> Self {
133        self.steps.push(TestAgentStep::cancel());
134        self
135    }
136
137    pub fn switch_model(mut self, provider: impl StreamingModelProvider + 'static) -> Self {
138        self.steps.push(TestAgentStep::switch_model(provider));
139        self
140    }
141
142    pub fn replace_conversation(mut self, messages: Vec<ChatMessage>) -> Self {
143        self.steps.push(TestAgentStep::replace_conversation(messages));
144        self
145    }
146
147    pub fn wait_for(mut self, predicate: impl Fn(&AgentEvent) -> bool + Send + 'static) -> Self {
148        self.steps.push(TestAgentStep::wait_for(predicate));
149        self
150    }
151
152    pub fn wait_for_turn_end(mut self) -> Self {
153        self.steps.push(TestAgentStep::wait_for_turn_end());
154        self
155    }
156
157    pub fn wait_for_compaction_start(mut self) -> Self {
158        self.steps.push(TestAgentStep::wait_for_compaction_start());
159        self
160    }
161
162    pub fn wait_for_retry(mut self, attempt: u32) -> Self {
163        self.steps.push(TestAgentStep::wait_for_retry(attempt));
164        self
165    }
166
167    /// Run an arbitrary side effect between scenario steps, e.g. releasing a
168    /// paused LLM stream so a queued message can be injected mid-turn.
169    pub fn perform(mut self, action: impl FnOnce() + Send + 'static) -> Self {
170        self.steps.push(TestAgentStep::perform(action));
171        self
172    }
173}
174
175impl From<Vec<TestAgentStep>> for TestScenario {
176    fn from(steps: Vec<TestAgentStep>) -> Self {
177        Self { steps }
178    }
179}
180
181/// Result of running a test agent, including messages and captured contexts.
182pub struct TestAgentResult {
183    pub messages: Vec<AgentEvent>,
184    pub captured_contexts: Arc<Mutex<Vec<Context>>>,
185}
186
187/// Error returned by [`TestAgentBuilder::run`], [`TestAgentBuilder::run_trace`], and
188/// [`TestAgentBuilder::run_with_context`].
189#[derive(Debug, thiserror::Error)]
190pub enum TestAgentError {
191    #[error(transparent)]
192    Agent(#[from] AgentError),
193    #[error("failed to send command to the test agent: {0}")]
194    SendCommand(#[from] mpsc::error::SendError<Command>),
195}
196
197pub type TestResult<T> = std::result::Result<T, TestAgentError>;
198
199struct ProviderTestConfig {
200    responses: Vec<Vec<Result<LlmResponse, LlmError>>>,
201    model: Option<LlmModel>,
202    context_window: Option<u32>,
203    pause: Option<(usize, usize, Arc<Notify>)>,
204}
205
206struct AgentTestConfig {
207    context_window_override: Option<u32>,
208    timeout: Option<Duration>,
209    max_auto_continues: Option<u32>,
210    retry_config: Option<RetryConfig>,
211    observers: Vec<Box<dyn AgentObserver>>,
212    mcp_server: Option<(String, FakeMcpServer)>,
213    initial_messages: Vec<ChatMessage>,
214    system_prompts: Vec<Prompt>,
215    session_affinity_key: Option<String>,
216    compaction: Option<CompactionConfig>,
217    model_settings: Option<ModelSettings>,
218}
219
220enum TestExecution {
221    CommandsUntilTurnEnd(Vec<Command>),
222    Scenario(TestScenario),
223}
224
225pub struct TestAgentBuilder {
226    provider: ProviderTestConfig,
227    agent: AgentTestConfig,
228    execution: Option<TestExecution>,
229}
230
231impl Default for TestAgentBuilder {
232    fn default() -> Self {
233        Self::new()
234    }
235}
236
237impl TestAgentBuilder {
238    pub fn new() -> Self {
239        Self {
240            provider: ProviderTestConfig { responses: Vec::new(), model: None, context_window: None, pause: None },
241            agent: AgentTestConfig {
242                context_window_override: None,
243                timeout: None,
244                max_auto_continues: None,
245                retry_config: None,
246                observers: Vec::new(),
247                mcp_server: Some(("test".to_string(), FakeMcpServer::new())),
248                initial_messages: Vec::new(),
249                system_prompts: Vec::new(),
250                session_affinity_key: None,
251                compaction: None,
252                model_settings: None,
253            },
254            execution: None,
255        }
256    }
257
258    pub fn commands(self, commands: Vec<Command>) -> Self {
259        self.with_execution(TestExecution::CommandsUntilTurnEnd(commands))
260    }
261
262    pub fn scenario(self, scenario: impl Into<TestScenario>) -> Self {
263        self.with_execution(TestExecution::Scenario(scenario.into()))
264    }
265
266    pub fn user_text(self, text: &str) -> Self {
267        self.commands(vec![Command::text(text)])
268    }
269
270    pub fn llm_responses(mut self, llm_responses: &[Vec<LlmResponse>]) -> Self {
271        self.provider.responses = llm_responses.iter().map(|turn| turn.iter().cloned().map(Ok).collect()).collect();
272        self
273    }
274
275    pub fn llm_result_responses(mut self, llm_responses: &[Vec<Result<LlmResponse, LlmError>>]) -> Self {
276        self.provider.responses = Vec::from(llm_responses);
277        self
278    }
279
280    pub fn model(mut self, model: LlmModel) -> Self {
281        self.provider.model = Some(model);
282        self
283    }
284
285    pub fn provider_context_window(mut self, window: Option<u32>) -> Self {
286        self.provider.context_window = window;
287        self
288    }
289
290    pub fn context_window_override(mut self, window: u32) -> Self {
291        self.agent.context_window_override = Some(window);
292        self
293    }
294
295    pub fn tool_timeout(mut self, timeout: Duration) -> Self {
296        self.agent.timeout = Some(timeout);
297        self
298    }
299
300    pub fn max_auto_continues(mut self, max: u32) -> Self {
301        self.agent.max_auto_continues = Some(max);
302        self
303    }
304
305    pub fn retry_config(mut self, config: RetryConfig) -> Self {
306        self.agent.retry_config = Some(config);
307        self
308    }
309
310    /// Run without the default fake MCP server when the scenario does not exercise tools.
311    pub fn without_mcp(mut self) -> Self {
312        self.agent.mcp_server = None;
313        self
314    }
315
316    /// Replace the default fake MCP server with a scripted server.
317    pub fn fake_mcp_server(mut self, name: &str, server: FakeMcpServer) -> Self {
318        self.agent.mcp_server = Some((name.to_string(), server));
319        self
320    }
321
322    /// Pre-populate the context with conversation history.
323    pub fn messages(mut self, messages: Vec<ChatMessage>) -> Self {
324        self.agent.initial_messages = messages;
325        self
326    }
327
328    /// Set the system prompt. Multiple prompts are concatenated with double
329    /// newlines, mirroring [`crate::core::AgentBuilder::system_prompt`].
330    pub fn system_prompt(mut self, prompt: Prompt) -> Self {
331        self.agent.system_prompts.push(prompt);
332        self
333    }
334
335    /// Set the session affinity key attached to every LLM call; defaults to a
336    /// fresh random key per agent.
337    pub fn session_affinity_key(mut self, key: impl Into<String>) -> Self {
338        self.agent.session_affinity_key = Some(key.into());
339        self
340    }
341
342    /// Configure context compaction settings.
343    pub fn compaction_config(mut self, config: CompactionConfig) -> Self {
344        self.agent.compaction = Some(config);
345        self
346    }
347
348    /// Set the model settings applied to every LLM call.
349    pub fn model_settings(mut self, settings: ModelSettings) -> Self {
350        self.agent.model_settings = Some(settings);
351        self
352    }
353
354    /// Pause the fake LLM stream at `turn_index` / `chunk_index` until
355    /// `release.notify_one()` is called. Used for deterministic timing tests.
356    pub fn pause_turn_after(mut self, turn_index: usize, chunk_index: usize, release: Arc<Notify>) -> Self {
357        self.provider.pause = Some((turn_index, chunk_index, release));
358        self
359    }
360
361    /// Attach an observer of the test agent's event stream.
362    pub fn observer(mut self, observer: Box<dyn AgentObserver>) -> Self {
363        self.agent.observers.push(observer);
364        self
365    }
366
367    pub async fn run(self) -> TestResult<Vec<AgentEvent>> {
368        let result = self.run_with_context().await?;
369        Ok(result.messages)
370    }
371
372    /// Runs the test agent with a recording observer attached and returns the
373    /// full event trace, including internal events.
374    pub async fn run_trace(self) -> TestResult<AgentTrace> {
375        let observer = FakeAgentObserver::new();
376        let events = observer.events();
377        self.observer(Box::new(observer)).run().await?;
378        Ok(AgentTrace::from_observer_events(&events))
379    }
380
381    /// Runs the test agent and returns both messages and captured contexts.
382    ///
383    /// Use this when you need to verify what context was passed to the LLM,
384    /// for example when testing that file attachments are properly formatted.
385    pub async fn run_with_context(self) -> TestResult<TestAgentResult> {
386        let Self { provider, agent: config, execution } = self;
387        let mut llm = FakeLlmProvider::from_results(provider.responses).with_context_window(provider.context_window);
388        if let Some(model) = provider.model {
389            llm = llm.with_model(model);
390        }
391        if let Some((turn_index, chunk_index, release)) = provider.pause {
392            llm = llm.pause_turn_after(turn_index, chunk_index, release);
393        }
394        let captured_contexts = llm.captured_contexts();
395
396        let mut mcp_spawn = match config.mcp_server {
397            Some((name, server)) => {
398                Some(mcp("/workspace").with_fake_mcp(name, server).spawn().await.map_err(AgentError::from)?)
399            }
400            None => None,
401        };
402
403        let mut builder = agent(llm);
404        if let Some(spawn) = &mut mcp_spawn {
405            let snapshot = spawn.block_until_ready().await.expect("bootstrap completes");
406            builder = builder.tools(spawn.handle().clone(), snapshot.tool_definitions());
407        }
408        if let Some(timeout) = config.timeout {
409            builder = builder.tool_timeout(timeout);
410        }
411        if let Some(max) = config.max_auto_continues {
412            builder = builder.max_auto_continues(max);
413        }
414        if let Some(retry) = config.retry_config {
415            builder = builder.retry(retry);
416        } else {
417            builder = builder.retry(RetryConfig::disabled());
418        }
419        for prompt in config.system_prompts {
420            builder = builder.system_prompt(prompt);
421        }
422        if let Some(key) = config.session_affinity_key {
423            builder = builder.session_affinity_key(key);
424        }
425        if let Some(compaction) = config.compaction {
426            builder = builder.compaction(compaction);
427        }
428        if let Some(settings) = config.model_settings {
429            builder = builder.model_settings(settings);
430        }
431        builder = builder.context_window(config.context_window_override);
432        if !config.initial_messages.is_empty() {
433            builder = builder.messages(config.initial_messages);
434        }
435        for observer in config.observers {
436            builder = builder.observer(observer);
437        }
438
439        let steps = match execution.expect("test agent requires commands(), user_text(), or scenario()") {
440            TestExecution::CommandsUntilTurnEnd(commands) => {
441                assert!(!commands.is_empty(), "commands() requires at least one command");
442                let mut steps = commands.into_iter().map(TestAgentStep::send).collect::<Vec<_>>();
443                steps.push(TestAgentStep::wait_for_turn_end());
444                steps
445            }
446            TestExecution::Scenario(scenario) => {
447                assert!(!scenario.steps.is_empty(), "scenario() requires at least one step");
448                scenario.steps
449            }
450        };
451        let (tx, mut rx, handle) = builder.spawn().await?;
452        let mut messages = Vec::new();
453
454        for step in steps {
455            match step {
456                TestAgentStep::Send(command) => tx.send(command).await?,
457                TestAgentStep::WaitFor(predicate) => loop {
458                    let message = rx.recv().await.expect("agent event channel closed before scenario step matched");
459                    let matched = predicate(&message);
460                    messages.push(message);
461                    if matched {
462                        break;
463                    }
464                },
465                TestAgentStep::Perform(action) => action(),
466            }
467        }
468        drop(tx);
469
470        handle.await_completion().await;
471
472        Ok(TestAgentResult { messages, captured_contexts })
473    }
474
475    fn with_execution(mut self, execution: TestExecution) -> Self {
476        assert!(self.execution.is_none(), "commands(), user_text(), and scenario() are mutually exclusive");
477        self.execution = Some(execution);
478        self
479    }
480}
aether_core/testing/utils.rs

aether_core/testing/
utils.rs
