feat(aggregator-discovery): create test double for 'AggregatorDiscoverer' trait

Author: jpraynaud

internal/mithril-aggregator-discovery/src/lib.rs

@@ -3,6 +3,7 @@
 
 mod interface;
 mod model;
+pub mod test;
 
 pub use interface::AggregatorDiscoverer;
 pub use model::{AggregatorEndpoint, MithrilNetwork};

internal/mithril-aggregator-discovery/src/test/double/discoverer.rs

@@ -0,0 +1,76 @@
+use std::collections::VecDeque;
+
+use tokio::sync::Mutex;
+
+use mithril_common::StdResult;
+
+use crate::{AggregatorDiscoverer, AggregatorEndpoint, MithrilNetwork};
+
+type AggregatorListReturn = StdResult<Vec<AggregatorEndpoint>>;
+
+/// A fake implementation of the [AggregatorDiscoverer] trait for testing purposes.
+pub struct AggregatorDiscovererFake {
+    results: Mutex<VecDeque<AggregatorListReturn>>,
+}
+
+impl AggregatorDiscovererFake {
+    /// Creates a new `AggregatorDiscovererFake` instance with the provided results.
+    pub fn new(results: Vec<AggregatorListReturn>) -> Self {
+        Self {
+            results: Mutex::new(VecDeque::from(results)),
+        }
+    }
+}
+
+#[async_trait::async_trait]
+impl AggregatorDiscoverer for AggregatorDiscovererFake {
+    async fn get_available_aggregators(
+        &self,
+        _network: MithrilNetwork,
+    ) -> StdResult<Vec<AggregatorEndpoint>> {
+        let mut results = self.results.lock().await;
+
+        let endpoints = results.pop_front().ok_or_else(|| {
+            anyhow::anyhow!("No more results available in AggregatorDiscovererFake")
+        })??;
+
+        Ok(endpoints)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+
+    #[tokio::test]
+    async fn get_available_aggregators_success() {
+        let consumer = AggregatorDiscovererFake::new(vec![
+            Ok(vec![AggregatorEndpoint::new("test-1".to_string())]),
+            Ok(vec![AggregatorEndpoint::new("test-2".to_string())]),
+        ]);
+
+        let messages = consumer
+            .get_available_aggregators(MithrilNetwork::dummy())
+            .await
+            .unwrap();
+
+        assert_eq!(
+            vec![AggregatorEndpoint::new("test-1".to_string())],
+            messages
+        );
+    }
+
+    #[tokio::test]
+    async fn consume_messages_failure() {
+        let consumer = AggregatorDiscovererFake::new(vec![
+            Err(anyhow::anyhow!("Test error")),
+            Ok(vec![AggregatorEndpoint::new("test-2".to_string())]),
+        ]);
+
+        consumer
+            .get_available_aggregators(MithrilNetwork::dummy())
+            .await
+            .expect_err("AggregatorDiscovererFake should return an error");
+    }
+}

internal/mithril-aggregator-discovery/src/test/double/mod.rs

@@ -0,0 +1,7 @@
+//! Test doubles
+//!
+//! Enable unit testing with controlled inputs and predictable behavior.
+
+mod discoverer;
+
+pub use discoverer::*;

internal/mithril-aggregator-discovery/src/test/mod.rs

@@ -0,0 +1,7 @@
+//! Test utilities.
+//!
+//! ⚠ Do not use in production code ⚠
+//!
+//! This module provides in particular test doubles for the traits defined in this crate.
+
+pub mod double;