ruby-sdk/test/mcp/client_test.rb
Koichi ITO 88e1f9a840 Support completion/complete per MCP specification
## Motivation and Context

The MCP specification defines `completion/complete` for providing autocompletion
suggestions for prompt arguments and resource template URIs.
The Ruby SDK previously had only a no-op handler that returned empty results,
with no way for users to define custom completion logic.

This aligns the Ruby SDK with the Python and TypeScript SDKs,
both of which support user-defined completion handlers.

## How Has This Been Tested?

Server tests cover: default handler, custom handler for `ref/prompt` and `ref/resource`,
context argument passing, 100-item truncation, and error responses for nonexistent prompts,
nonexistent resource templates, and invalid ref types.

Client tests cover: request structure, context parameter inclusion,
and fallback when result is missing.

## Breaking Changes

None. The existing default no-op handler behavior is preserved.
The `completion_handler` method is purely additive. The only behavioral change
is that `completion/complete` requests now validate that the referenced prompt
or resource template exists before calling the handler,
returning an `invalid_params` error for unknown references.
2026-04-03 01:35:07 +09:00

541 lines
19 KiB
Ruby

# frozen_string_literal: true
require "test_helper"
require "securerandom"
module MCP
class ClientTest < Minitest::Test
def test_tools_sends_request_to_transport_and_returns_tools_array
transport = mock
mock_response = {
"result" => {
"tools" => [
{ "name" => "tool1", "description" => "tool1", "inputSchema" => {} },
{ "name" => "tool2", "description" => "tool2", "inputSchema" => {} },
],
},
}
# Only checking for the essential parts of the request
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "tools/list" && args.dig(:request, :jsonrpc) == "2.0"
end.returns(mock_response).once
client = Client.new(transport: transport)
tools = client.tools
assert_equal(2, tools.size)
assert_equal("tool1", tools.first.name)
assert_equal("tool2", tools.last.name)
end
def test_tools_returns_empty_array_when_no_tools
transport = mock
mock_response = { "result" => { "tools" => [] } }
# Only checking for the essential parts of the request
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "tools/list" && args.dig(:request, :jsonrpc) == "2.0"
end.returns(mock_response).once
client = Client.new(transport: transport)
tools = client.tools
assert_equal([], tools)
end
def test_call_tool_sends_request_to_transport_and_returns_content
transport = mock
tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {})
arguments = { foo: "bar" }
mock_response = {
"result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] },
}
# Only checking for the essential parts of the request
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "tools/call" &&
args.dig(:request, :jsonrpc) == "2.0" &&
args.dig(:request, :params, :name) == "tool1" &&
args.dig(:request, :params, :arguments) == arguments
end.returns(mock_response).once
client = Client.new(transport: transport)
result = client.call_tool(tool: tool, arguments: arguments)
content = result.dig("result", "content")
assert_equal([{ type: "text", text: "Hello, world!" }], content)
end
def test_call_tool_by_name
transport = mock
arguments = { foo: "bar" }
mock_response = {
"result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] },
}
transport.expects(:send_request).with do |args|
args.dig(:request, :params, :name) == "tool1" &&
args.dig(:request, :params, :arguments) == arguments
end.returns(mock_response).once
client = Client.new(transport: transport)
result = client.call_tool(name: "tool1", arguments: arguments)
content = result.dig("result", "content")
assert_equal([{ type: "text", text: "Hello, world!" }], content)
end
def test_call_tool_raises_when_no_name_or_tool
client = Client.new(transport: mock)
error = assert_raises(ArgumentError) { client.call_tool(arguments: { foo: "bar" }) }
assert_equal("Either `name:` or `tool:` must be provided.", error.message)
end
def test_resources_sends_request_to_transport_and_returns_resources_array
transport = mock
mock_response = {
"result" => {
"resources" => [
{ "name" => "resource1", "uri" => "file:///path/to/resource1", "description" => "First resource" },
{ "name" => "resource2", "uri" => "file:///path/to/resource2", "description" => "Second resource" },
],
},
}
# Only checking for the essential parts of the request
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "resources/list" && args.dig(:request, :jsonrpc) == "2.0"
end.returns(mock_response).once
client = Client.new(transport: transport)
resources = client.resources
assert_equal(2, resources.size)
assert_equal("resource1", resources.first["name"])
assert_equal("file:///path/to/resource1", resources.first["uri"])
assert_equal("resource2", resources.last["name"])
assert_equal("file:///path/to/resource2", resources.last["uri"])
end
def test_resources_returns_empty_array_when_no_resources
transport = mock
mock_response = { "result" => { "resources" => [] } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
resources = client.resources
assert_equal([], resources)
end
def test_read_resource_sends_request_to_transport_and_returns_contents
transport = mock
uri = "file:///path/to/resource.txt"
mock_response = {
"result" => {
"contents" => [
{ "uri" => uri, "mimeType" => "text/plain", "text" => "Hello, world!" },
],
},
}
# Only checking for the essential parts of the request
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "resources/read" &&
args.dig(:request, :jsonrpc) == "2.0" &&
args.dig(:request, :params, :uri) == uri
end.returns(mock_response).once
client = Client.new(transport: transport)
contents = client.read_resource(uri: uri)
assert_equal(1, contents.size)
assert_equal(uri, contents.first["uri"])
assert_equal("text/plain", contents.first["mimeType"])
assert_equal("Hello, world!", contents.first["text"])
end
def test_read_resource_returns_empty_array_when_no_contents
transport = mock
uri = "file:///path/to/nonexistent.txt"
mock_response = { "result" => {} }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
contents = client.read_resource(uri: uri)
assert_equal([], contents)
end
def test_resource_templates_sends_request_to_transport_and_returns_resource_templates_array
transport = mock
mock_response = {
"result" => {
"resourceTemplates" => [
{ "name" => "template1", "uriTemplate" => "file:///path/{filename}", "description" => "First template" },
{ "name" => "template2", "uriTemplate" => "http://example.com/{id}", "description" => "Second template" },
],
},
}
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "resources/templates/list" && args.dig(:request, :jsonrpc) == "2.0"
end.returns(mock_response).once
client = Client.new(transport: transport)
resource_templates = client.resource_templates
assert_equal(2, resource_templates.size)
assert_equal("template1", resource_templates.first["name"])
assert_equal("file:///path/{filename}", resource_templates.first["uriTemplate"])
assert_equal("template2", resource_templates.last["name"])
assert_equal("http://example.com/{id}", resource_templates.last["uriTemplate"])
end
def test_resource_templates_returns_empty_array_when_no_resource_templates
transport = mock
mock_response = { "result" => { "resourceTemplates" => [] } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
resource_templates = client.resource_templates
assert_equal([], resource_templates)
end
def test_prompts_sends_request_to_transport_and_returns_prompts_array
transport = mock
mock_response = {
"result" => {
"prompts" => [
{
"name" => "prompt_1",
"description" => "First prompt",
"arguments" => [
{
"name" => "code_1",
"description" => "The code_1 to review",
"required" => true,
},
],
},
{
"name" => "prompt_2",
"description" => "Second prompt",
"arguments" => [
{
"name" => "code_2",
"description" => "The code_2 to review",
"required" => true,
},
],
},
],
},
}
# Only checking for the essential parts of the request
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "prompts/list" && args.dig(:request, :jsonrpc) == "2.0"
end.returns(mock_response).once
client = Client.new(transport: transport)
prompts = client.prompts
assert_equal(2, prompts.size)
assert_equal("prompt_1", prompts.first["name"])
assert_equal("First prompt", prompts.first["description"])
assert_equal("code_1", prompts.first["arguments"].first["name"])
assert_equal("The code_1 to review", prompts.first["arguments"].first["description"])
assert(prompts.first["arguments"].first["required"])
assert_equal("prompt_2", prompts.last["name"])
assert_equal("Second prompt", prompts.last["description"])
assert_equal("code_2", prompts.last["arguments"].first["name"])
assert_equal("The code_2 to review", prompts.last["arguments"].first["description"])
assert(prompts.last["arguments"].first["required"])
end
def test_prompts_returns_empty_array_when_no_prompts
transport = mock
mock_response = { "result" => { "prompts" => [] } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
prompts = client.prompts
assert_equal([], prompts)
end
def test_get_prompt_sends_request_to_transport_and_returns_contents
transport = mock
name = "first_prompt"
mock_response = {
"result" => {
"description" => "First prompt",
"messages" => [
{
"role" => "user",
"content" => {
"text" => "First prompt content",
"type" => "text",
},
},
],
},
}
# Only checking for the essential parts of the request
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "prompts/get" &&
args.dig(:request, :jsonrpc) == "2.0" &&
args.dig(:request, :params, :name) == name
end.returns(mock_response).once
client = Client.new(transport: transport)
contents = client.get_prompt(name: name)
assert_equal("First prompt", contents["description"])
assert_equal("user", contents["messages"].first["role"])
assert_equal("First prompt content", contents["messages"].first["content"]["text"])
end
def test_get_prompt_returns_empty_hash_when_no_contents
transport = mock
name = "nonexistent_prompt"
mock_response = { "result" => {} }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
contents = client.get_prompt(name: name)
assert_equal({}, contents)
end
def test_get_prompt_returns_empty_hash
transport = mock
name = "nonexistent_prompt"
mock_response = {}
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
contents = client.get_prompt(name: name)
assert_equal({}, contents)
end
def test_call_tool_includes_meta_progress_token_when_provided
transport = mock
tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {})
arguments = { foo: "bar" }
progress_token = "my-progress-token"
mock_response = {
"result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] },
}
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "tools/call" &&
args.dig(:request, :params, :_meta, :progressToken) == progress_token &&
args.dig(:request, :params, :name) == "tool1" &&
args.dig(:request, :params, :arguments) == arguments
end.returns(mock_response).once
client = Client.new(transport: transport)
client.call_tool(tool: tool, arguments: arguments, progress_token: progress_token)
end
def test_call_tool_omits_meta_when_no_progress_token
transport = mock
tool = MCP::Client::Tool.new(name: "tool1", description: "tool1", input_schema: {})
arguments = { foo: "bar" }
mock_response = {
"result" => { "content" => [{ "type": "text", "text": "Hello, world!" }] },
}
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "tools/call" &&
args.dig(:request, :params, :name) == "tool1" &&
args.dig(:request, :params).key?(:_meta) == false
end.returns(mock_response).once
client = Client.new(transport: transport)
client.call_tool(tool: tool, arguments: arguments)
end
def test_tools_raises_server_error_on_error_response
transport = mock
mock_response = { "error" => { "code" => -32_601, "message" => "Method not found" } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
error = assert_raises(Client::ServerError) { client.tools }
assert_equal(-32_601, error.code)
assert_equal("Method not found", error.message)
end
def test_resources_raises_server_error_on_error_response
transport = mock
mock_response = { "error" => { "code" => -32_602, "message" => "Invalid params" } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
error = assert_raises(Client::ServerError) { client.resources }
assert_equal(-32_602, error.code)
end
def test_read_resource_raises_server_error_on_error_response
transport = mock
mock_response = { "error" => { "code" => -32_602, "message" => "Resource not found" } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
assert_raises(Client::ServerError) { client.read_resource(uri: "file:///missing") }
end
def test_get_prompt_raises_server_error_on_error_response
transport = mock
mock_response = { "error" => { "code" => -32_602, "message" => "Prompt not found" } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
assert_raises(Client::ServerError) { client.get_prompt(name: "missing") }
end
def test_prompts_raises_server_error_on_error_response
transport = mock
mock_response = { "error" => { "code" => -32_601, "message" => "Method not found" } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
assert_raises(Client::ServerError) { client.prompts }
end
def test_resource_templates_raises_server_error_on_error_response
transport = mock
mock_response = { "error" => { "code" => -32_601, "message" => "Method not found" } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
assert_raises(Client::ServerError) { client.resource_templates }
end
def test_call_tool_raises_server_error_on_error_response
transport = mock
mock_response = { "error" => { "code" => -32_602, "message" => "Tool not found" } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
error = assert_raises(Client::ServerError) { client.call_tool(name: "missing") }
assert_equal(-32_602, error.code)
end
def test_server_error_includes_data_field
transport = mock
mock_response = {
"error" => { "code" => -32_603, "message" => "Internal error", "data" => "extra details" },
}
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
error = assert_raises(Client::ServerError) { client.tools }
assert_equal("extra details", error.data)
end
def test_complete_raises_server_error_on_error_response
transport = mock
mock_response = { "error" => { "code" => -32_602, "message" => "Invalid params" } }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
error = assert_raises(Client::ServerError) { client.complete(ref: { type: "ref/prompt", name: "missing" }, argument: { name: "arg", value: "" }) }
assert_equal(-32_602, error.code)
end
def test_complete_sends_request_and_returns_completion_result
transport = mock
mock_response = {
"result" => {
"completion" => {
"values" => ["python", "pytorch"],
"hasMore" => false,
},
},
}
transport.expects(:send_request).with do |args|
args.dig(:request, :method) == "completion/complete" &&
args.dig(:request, :jsonrpc) == "2.0" &&
args.dig(:request, :params, :ref) == { type: "ref/prompt", name: "code_review" } &&
args.dig(:request, :params, :argument) == { name: "language", value: "py" } &&
!args.dig(:request, :params).key?(:context)
end.returns(mock_response).once
client = Client.new(transport: transport)
result = client.complete(
ref: { type: "ref/prompt", name: "code_review" },
argument: { name: "language", value: "py" },
)
assert_equal(["python", "pytorch"], result["values"])
refute(result["hasMore"])
end
def test_complete_includes_context_when_provided
transport = mock
mock_response = {
"result" => {
"completion" => {
"values" => ["flask"],
"hasMore" => false,
},
},
}
transport.expects(:send_request).with do |args|
args.dig(:request, :params, :context) == { arguments: { language: "python" } }
end.returns(mock_response).once
client = Client.new(transport: transport)
result = client.complete(
ref: { type: "ref/prompt", name: "code_review" },
argument: { name: "framework", value: "fla" },
context: { arguments: { language: "python" } },
)
assert_equal(["flask"], result["values"])
end
def test_complete_returns_default_when_result_is_missing
transport = mock
mock_response = { "result" => {} }
transport.expects(:send_request).returns(mock_response).once
client = Client.new(transport: transport)
result = client.complete(
ref: { type: "ref/prompt", name: "test" },
argument: { name: "arg", value: "" },
)
assert_equal([], result["values"])
refute(result["hasMore"])
end
end
end