Struct TestClient 

pub struct TestClient { /* private fields */ }

An ergonomic test client for MCP servers.

Wraps an McpRouter and JsonRpcService to provide typed, concise methods for testing MCP server behavior. All methods that expect successful responses will panic on JSON-RPC errors, which is appropriate for test code.

Construction

Use TestClient::from_router to create a client from an existing router:

use tower_mcp::{McpRouter, TestClient};

let router = McpRouter::new().server_info("test", "1.0.0");
let mut client = TestClient::from_router(router);

Implementations

impl TestClient

pub fn from_router(router: McpRouter) -> Self

Create a new test client from an McpRouter.

Sets up a notification channel and wraps the router in a JsonRpcService for JSON-RPC framing.

pub async fn initialize(&mut self) -> Value

Send an initialize request and the initialized notification.

Returns the raw JSON result from the initialize response. Panics if initialization fails.

pub async fn list_tools(&mut self) -> Vec<Value>

List all tools registered on the server.

Returns the tools array from the response. Panics on error.

pub async fn call_tool(&mut self, name: &str, args: Value) -> CallToolResult

Call a tool by name with the given arguments.

Returns a typed CallToolResult. Panics on JSON-RPC errors.

Example

let result = client.call_tool("echo", json!({"message": "hi"})).await;
assert_eq!(result.first_text(), Some("hi"));

pub async fn call_tool_raw(&mut self, name: &str, args: Value) -> Value

Call a tool and return the raw JSON response.

Useful when you need to inspect fields not covered by CallToolResult.

pub async fn call_tool_json(&mut self, name: &str, args: Value) -> Value

Call a tool and parse the result as a JSON Value.

Panics if the tool call fails, returns an error, or has no parseable content.

Example

let value = client.call_tool_json("search", json!({"q": "rust"})).await;
assert!(value["results"].is_array());

pub async fn call_tool_typed<T: DeserializeOwned>( &mut self, name: &str, args: Value, ) -> T

Call a tool and deserialize the result into a typed value.

Panics if the tool call fails, returns an error, or deserialization fails.

Example

let result: SearchResult = client.call_tool_typed("search", json!({"q": "rust"})).await;
assert!(result.count > 0);

pub async fn call_tool_expect_error(&mut self, name: &str, args: Value) -> Value

Call a tool and assert that it returns an error.

Panics if the tool call succeeds without an error. Returns the raw JSON response body (which may be a CallToolResult with isError: true or a JSON-RPC error).

pub async fn list_resources(&mut self) -> Vec<Value>

List all resources registered on the server.

Returns the resources array from the response. Panics on error.

pub async fn read_resource(&mut self, uri: &str) -> ReadResourceResult

Read a resource by URI.

Returns a typed ReadResourceResult. Panics on JSON-RPC errors.

pub async fn list_prompts(&mut self) -> Vec<Value>

List all prompts registered on the server.

Returns the prompts array from the response. Panics on error.

pub async fn get_prompt( &mut self, name: &str, args: HashMap<String, String>, ) -> GetPromptResult

Get a prompt by name with the given arguments.

Returns a typed GetPromptResult. Panics on JSON-RPC errors.

pub async fn complete(&mut self, params: Value) -> Value

Send a completion request with raw parameters.

Returns the raw JSON result. Panics on error.

pub async fn send_request( &mut self, method: &str, params: Option<Value>, ) -> Value

Send an arbitrary request and expect success.

This is an escape hatch for methods not covered by the typed helpers. Panics on JSON-RPC errors.

pub async fn send_request_expect_error( &mut self, method: &str, params: Option<Value>, ) -> Value

Send an arbitrary request and expect a JSON-RPC error.

Panics if the response is a success. Returns the error object as JSON.

pub fn try_recv_notification(&mut self) -> Option<ServerNotification>

Try to receive a notification without blocking.

Returns None if no notification is available.

pub fn drain_notifications(&mut self) -> Vec<ServerNotification>

Drain all pending notifications.

Returns all notifications that have been sent since the last drain.