test(provider): add integration tests for ProviderManager using MockProvider

- Introduce `MockProvider` with configurable models, health status, generation handlers, and error simulation.
- Add common test utilities and integration tests covering provider registration, model aggregation, request routing, error handling, and health refresh.

crates/owlen-providers/tests/common/mock_provider.rs

@@ -0,0 +1,106 @@
+use std::sync::Arc;
+
+use async_trait::async_trait;
+use futures::stream::{self, StreamExt};
+use owlen_core::Result as CoreResult;
+use owlen_core::provider::{
+    GenerateChunk, GenerateRequest, GenerateStream, ModelInfo, ModelProvider, ProviderMetadata,
+    ProviderStatus, ProviderType,
+};
+
+pub struct MockProvider {
+    metadata: ProviderMetadata,
+    models: Vec<ModelInfo>,
+    status: ProviderStatus,
+    #[allow(clippy::type_complexity)]
+    generate_handler: Option<Arc<dyn Fn(GenerateRequest) -> Vec<GenerateChunk> + Send + Sync>>,
+    generate_error: Option<Arc<dyn Fn() -> owlen_core::Error + Send + Sync>>,
+}
+
+impl MockProvider {
+    pub fn new(id: &str) -> Self {
+        let metadata = ProviderMetadata::new(
+            id,
+            format!("Mock Provider ({})", id),
+            ProviderType::Local,
+            false,
+        );
+
+        Self {
+            metadata,
+            models: vec![ModelInfo {
+                name: format!("{}-primary", id),
+                size_bytes: None,
+                capabilities: vec!["chat".into()],
+                description: Some("Mock model".into()),
+                provider: ProviderMetadata::new(id, "Mock", ProviderType::Local, false),
+                metadata: Default::default(),
+            }],
+            status: ProviderStatus::Available,
+            generate_handler: None,
+            generate_error: None,
+        }
+    }
+
+    pub fn with_models(mut self, models: Vec<ModelInfo>) -> Self {
+        self.models = models;
+        self
+    }
+
+    pub fn with_status(mut self, status: ProviderStatus) -> Self {
+        self.status = status;
+        self
+    }
+
+    pub fn with_generate_handler<F>(mut self, handler: F) -> Self
+    where
+        F: Fn(GenerateRequest) -> Vec<GenerateChunk> + Send + Sync + 'static,
+    {
+        self.generate_handler = Some(Arc::new(handler));
+        self
+    }
+
+    pub fn with_generate_error<F>(mut self, factory: F) -> Self
+    where
+        F: Fn() -> owlen_core::Error + Send + Sync + 'static,
+    {
+        self.generate_error = Some(Arc::new(factory));
+        self
+    }
+}
+
+#[async_trait]
+impl ModelProvider for MockProvider {
+    fn metadata(&self) -> &ProviderMetadata {
+        &self.metadata
+    }
+
+    async fn health_check(&self) -> CoreResult<ProviderStatus> {
+        Ok(self.status)
+    }
+
+    async fn list_models(&self) -> CoreResult<Vec<ModelInfo>> {
+        Ok(self.models.clone())
+    }
+
+    async fn generate_stream(&self, request: GenerateRequest) -> CoreResult<GenerateStream> {
+        if let Some(factory) = &self.generate_error {
+            return Err(factory());
+        }
+
+        let chunks = if let Some(handler) = &self.generate_handler {
+            (handler)(request)
+        } else {
+            vec![GenerateChunk::final_chunk()]
+        };
+
+        let stream = stream::iter(chunks.into_iter().map(Ok)).boxed();
+        Ok(Box::pin(stream))
+    }
+}
+
+impl From<MockProvider> for Arc<dyn ModelProvider> {
+    fn from(provider: MockProvider) -> Self {
+        Arc::new(provider)
+    }
+}

crates/owlen-providers/tests/common/mod.rs

@@ -0,0 +1 @@
+pub mod mock_provider;

crates/owlen-providers/tests/integration_test.rs

@@ -0,0 +1,117 @@
+mod common;
+
+use std::sync::Arc;
+
+use futures::StreamExt;
+
+use common::mock_provider::MockProvider;
+use owlen_core::config::Config;
+use owlen_core::provider::{
+    GenerateChunk, GenerateRequest, ModelInfo, ProviderManager, ProviderType,
+};
+
+#[allow(dead_code)]
+fn base_config() -> Config {
+    Config {
+        providers: Default::default(),
+        ..Default::default()
+    }
+}
+
+fn make_model(name: &str, provider: &str) -> ModelInfo {
+    ModelInfo {
+        name: name.into(),
+        size_bytes: None,
+        capabilities: vec!["chat".into()],
+        description: Some("mock".into()),
+        provider: owlen_core::provider::ProviderMetadata::new(
+            provider,
+            provider,
+            ProviderType::Local,
+            false,
+        ),
+        metadata: Default::default(),
+    }
+}
+
+#[tokio::test]
+async fn registers_providers_and_lists_ids() {
+    let manager = ProviderManager::default();
+    let provider: Arc<dyn owlen_core::provider::ModelProvider> = MockProvider::new("mock-a").into();
+
+    manager.register_provider(provider).await;
+    let ids = manager.provider_ids().await;
+
+    assert_eq!(ids, vec!["mock-a".to_string()]);
+}
+
+#[tokio::test]
+async fn aggregates_models_across_providers() {
+    let manager = ProviderManager::default();
+    let provider_a = MockProvider::new("mock-a").with_models(vec![make_model("alpha", "mock-a")]);
+    let provider_b = MockProvider::new("mock-b").with_models(vec![make_model("beta", "mock-b")]);
+
+    manager.register_provider(provider_a.into()).await;
+    manager.register_provider(provider_b.into()).await;
+
+    let models = manager.list_all_models().await.unwrap();
+    assert_eq!(models.len(), 2);
+    assert!(models.iter().any(|m| m.model.name == "alpha"));
+    assert!(models.iter().any(|m| m.model.name == "beta"));
+}
+
+#[tokio::test]
+async fn routes_generation_to_specific_provider() {
+    let manager = ProviderManager::default();
+    let provider = MockProvider::new("mock-gen").with_generate_handler(|_req| {
+        vec![
+            GenerateChunk::from_text("hello"),
+            GenerateChunk::final_chunk(),
+        ]
+    });
+
+    manager.register_provider(provider.into()).await;
+
+    let request = GenerateRequest::new("mock-gen::primary");
+    let mut stream = manager.generate("mock-gen", request).await.unwrap();
+    let mut collected = Vec::new();
+    while let Some(chunk) = stream.next().await {
+        collected.push(chunk.unwrap());
+    }
+
+    assert_eq!(collected.len(), 2);
+    assert_eq!(collected[0].text.as_deref(), Some("hello"));
+    assert!(collected[1].is_final);
+}
+
+#[tokio::test]
+async fn marks_provider_unavailable_on_error() {
+    let manager = ProviderManager::default();
+    let provider = MockProvider::new("flaky")
+        .with_generate_error(|| owlen_core::Error::Network("boom".into()));
+
+    manager.register_provider(provider.into()).await;
+    let request = GenerateRequest::new("flaky::model");
+    let result = manager.generate("flaky", request).await;
+    assert!(result.is_err());
+
+    let status = manager.provider_status("flaky").await.unwrap();
+    assert!(matches!(
+        status,
+        owlen_core::provider::ProviderStatus::Unavailable
+    ));
+}
+
+#[tokio::test]
+async fn health_refresh_updates_status_cache() {
+    let manager = ProviderManager::default();
+    let provider =
+        MockProvider::new("healthy").with_status(owlen_core::provider::ProviderStatus::Available);
+
+    manager.register_provider(provider.into()).await;
+    let statuses = manager.refresh_health().await;
+    assert_eq!(
+        statuses.get("healthy"),
+        Some(&owlen_core::provider::ProviderStatus::Available)
+    );
+}