test: add test for to_readable_string

crates/goose/tests/tool_request_to_readable_string.rs

@@ -0,0 +1,34 @@
+use goose::conversation::message::ToolRequest;
+use mcp_core::ToolCall;
+use serde_json::json;
+
+// This test targets: ToolRequest::to_readable_string
+// It verifies that a successful tool call renders a readable string with
+// pretty-printed JSON arguments and includes the tool name.
+#[test]
+fn test_tool_request_to_readable_string_pretty_json() {
+    let tool_call = ToolCall::new(
+        "fetch_user",
+        json!({
+            "id": 42,
+            "active": true,
+            "details": {"level": 3}
+        }),
+    );
+
+    let req = ToolRequest {
+        id: "req-1".to_string(),
+        tool_call: Ok(tool_call),
+    };
+
+    let readable = req.to_readable_string();
+
+    // Starts with the expected tool prefix
+    assert!(readable.starts_with("Tool: fetch_user, Args: {"));
+
+    // Pretty JSON should contain newlines and formatted key/value pairs
+    assert!(readable.contains('\n'));
+    assert!(readable.contains("\"id\": 42"));
+    assert!(readable.contains("\"active\": true"));
+    assert!(readable.contains("\"details\": {"));
+}