progressive context thinning

crates/g3-core/tests/test_context_thinning.rs

@@ -0,0 +1,157 @@
+use g3_core::ContextWindow;
+use g3_providers::{Message, MessageRole};
+
+#[test]
+fn test_thinning_thresholds() {
+    let mut context = ContextWindow::new(10000);
+    
+    // At 0%, should not thin
+    assert!(!context.should_thin());
+    
+    // Simulate reaching 50% usage
+    context.used_tokens = 5000;
+    assert!(context.should_thin());
+    
+    // After thinning at 50%, should not thin again until next threshold
+    context.last_thinning_percentage = 50;
+    assert!(!context.should_thin());
+    
+    // At 60%, should thin again
+    context.used_tokens = 6000;
+    assert!(context.should_thin());
+    
+    // After thinning at 60%, should not thin
+    context.last_thinning_percentage = 60;
+    assert!(!context.should_thin());
+    
+    // At 70%, should thin
+    context.used_tokens = 7000;
+    assert!(context.should_thin());
+    
+    // At 80%, should thin
+    context.last_thinning_percentage = 70;
+    context.used_tokens = 8000;
+    assert!(context.should_thin());
+    
+    // After 80%, should not thin (compaction takes over)
+    context.last_thinning_percentage = 80;
+    context.used_tokens = 8500;
+    assert!(!context.should_thin());
+}
+
+#[test]
+fn test_thin_context_basic() {
+    let mut context = ContextWindow::new(10000);
+    
+    // Add some messages to the first third
+    for i in 0..9 {
+        if i % 2 == 0 {
+            context.add_message(Message {
+                role: MessageRole::Assistant,
+                content: format!("Assistant message {}", i),
+            });
+        } else {
+            // Add tool results with varying sizes
+            let content = if i == 1 {
+                // Large tool result (> 1000 chars)
+                format!("Tool result: {}", "x".repeat(1500))
+            } else if i == 3 {
+                // Another large tool result
+                format!("Tool result: {}", "y".repeat(2000))
+            } else {
+                // Small tool result (< 1000 chars)
+                format!("Tool result: small result {}", i)
+            };
+            
+            context.add_message(Message {
+                role: MessageRole::User,
+                content,
+            });
+        }
+    }
+    
+    // Trigger thinning at 50%
+    context.used_tokens = 5000;
+    let summary = context.thin_context();
+    
+    println!("Thinning summary: {}", summary);
+    
+    // Should have thinned at least 1 large tool result in the first third
+    assert!(summary.contains("1 tool result"), "Summary was: {}", summary);
+    assert!(summary.contains("50%"));
+    
+    // Check that the large tool results were replaced
+    let first_third_end = context.conversation_history.len() / 3;
+    for i in 0..first_third_end {
+        if let Some(msg) = context.conversation_history.get(i) {
+            if matches!(msg.role, MessageRole::User) && msg.content.starts_with("Tool result:") {
+                if msg.content.len() > 1000 {
+                    panic!("Found un-thinned large tool result at index {}", i);
+                }
+            }
+        }
+    }
+}
+
+#[test]
+fn test_thin_context_no_large_results() {
+    let mut context = ContextWindow::new(10000);
+    
+    // Add only small messages
+    for i in 0..9 {
+        context.add_message(Message {
+            role: MessageRole::User,
+            content: format!("Tool result: small {}", i),
+        });
+    }
+    
+    context.used_tokens = 5000;
+    let summary = context.thin_context();
+    
+    // Should report no large results found
+    assert!(summary.contains("no large tool results found"));
+}
+
+#[test]
+fn test_thin_context_only_affects_first_third() {
+    let mut context = ContextWindow::new(10000);
+    
+    // Add 12 messages (first third = 4 messages)
+    for i in 0..12 {
+        let content = if i % 2 == 1 {
+            // All odd indices are large tool results
+            format!("Tool result: {}", "x".repeat(1500))
+        } else {
+            format!("Assistant message {}", i)
+        };
+        
+        let role = if i % 2 == 1 {
+            MessageRole::User
+        } else {
+            MessageRole::Assistant
+        };
+        
+        context.add_message(Message { role, content });
+    }
+    
+    context.used_tokens = 5000;
+    let summary = context.thin_context();
+    
+    // First third is 4 messages (indices 0-3), so only indices 1 and 3 should be thinned
+    // That's 2 tool results
+    assert!(summary.contains("2 tool results"));
+    
+    // Check that messages after the first third are NOT thinned
+    let first_third_end = context.conversation_history.len() / 3;
+    for i in first_third_end..context.conversation_history.len() {
+        if let Some(msg) = context.conversation_history.get(i) {
+            if matches!(msg.role, MessageRole::User) && msg.content.starts_with("Tool result:") {
+                // These should still be large (not thinned)
+                if i % 2 == 1 {
+                    assert!(msg.content.len() > 1000, 
+                        "Message at index {} should not have been thinned", i);
+                }
+            }
+        }
+    }
+}