grpc-swift-protobuf/Tests/GRPCProtobufCodeGenTests/ProtobufCodeGeneratorTests.swift

/*
 * Copyright 2024, gRPC Authors All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import GRPCCodeGen
import GRPCProtobufCodeGen
import SwiftProtobufPluginLibrary
import Testing

struct ProtobufCodeGeneratorTests {
  @Suite("Self-contained service (test-service.proto)")
  struct TestService: UsesDescriptorSet {
    static let descriptorSetName = "test-service"
    static let fileDescriptorName = "test-service"

    @Test("Generate", arguments: [CodeGenerator.Config.AccessLevel.internal])
    func generate(accessLevel: GRPCCodeGen.CodeGenerator.Config.AccessLevel) throws {
      let generator = ProtobufCodeGenerator(
        config: CodeGenerator.Config(
          accessLevel: accessLevel,
          accessLevelOnImports: false,
          client: true,
          server: true,
          indentation: 2
        )
      )

      let access: String
      switch accessLevel {
      case .public:
        access = "public"
      case .internal:
        access = "internal"
      case .package:
        access = "package"
      default:
        fatalError()
      }

      let generated = try generator.generateCode(
        fileDescriptor: Self.fileDescriptor,
        protoFileModuleMappings: ProtoFileToModuleMappings(),
        extraModuleImports: []
      )

      let expected = """
        /// Leading trivia.

        // DO NOT EDIT.
        // swift-format-ignore-file
        //
        // Generated by the gRPC Swift generator plugin for the protocol buffer compiler.
        // Source: test-service.proto
        //
        // For information on using the generated types, please see the documentation:
        //   https://github.com/grpc/grpc-swift

        import GRPCCore
        import GRPCProtobuf

        // MARK: - test.TestService

        /// Namespace containing generated types for the "test.TestService" service.
        \(access) enum Test_TestService {
          /// Service descriptor for the "test.TestService" service.
          \(access) static let descriptor = GRPCCore.ServiceDescriptor(fullyQualifiedService: "test.TestService")
          /// Namespace for method metadata.
          \(access) enum Method {
            /// Namespace for "Unary" metadata.
            \(access) enum Unary {
              /// Request type for "Unary".
              \(access) typealias Input = Test_TestInput
              /// Response type for "Unary".
              \(access) typealias Output = Test_TestOutput
              /// Descriptor for "Unary".
              \(access) static let descriptor = GRPCCore.MethodDescriptor(
                service: GRPCCore.ServiceDescriptor(fullyQualifiedService: "test.TestService"),
                method: "Unary"
              )
            }
            /// Namespace for "ClientStreaming" metadata.
            \(access) enum ClientStreaming {
              /// Request type for "ClientStreaming".
              \(access) typealias Input = Test_TestInput
              /// Response type for "ClientStreaming".
              \(access) typealias Output = Test_TestOutput
              /// Descriptor for "ClientStreaming".
              \(access) static let descriptor = GRPCCore.MethodDescriptor(
                service: GRPCCore.ServiceDescriptor(fullyQualifiedService: "test.TestService"),
                method: "ClientStreaming"
              )
            }
            /// Namespace for "ServerStreaming" metadata.
            \(access) enum ServerStreaming {
              /// Request type for "ServerStreaming".
              \(access) typealias Input = Test_TestInput
              /// Response type for "ServerStreaming".
              \(access) typealias Output = Test_TestOutput
              /// Descriptor for "ServerStreaming".
              \(access) static let descriptor = GRPCCore.MethodDescriptor(
                service: GRPCCore.ServiceDescriptor(fullyQualifiedService: "test.TestService"),
                method: "ServerStreaming"
              )
            }
            /// Namespace for "BidirectionalStreaming" metadata.
            \(access) enum BidirectionalStreaming {
              /// Request type for "BidirectionalStreaming".
              \(access) typealias Input = Test_TestInput
              /// Response type for "BidirectionalStreaming".
              \(access) typealias Output = Test_TestOutput
              /// Descriptor for "BidirectionalStreaming".
              \(access) static let descriptor = GRPCCore.MethodDescriptor(
                service: GRPCCore.ServiceDescriptor(fullyQualifiedService: "test.TestService"),
                method: "BidirectionalStreaming"
              )
            }
            /// Descriptors for all methods in the "test.TestService" service.
            \(access) static let descriptors: [GRPCCore.MethodDescriptor] = [
              Unary.descriptor,
              ClientStreaming.descriptor,
              ServerStreaming.descriptor,
              BidirectionalStreaming.descriptor
            ]
          }
        }

        extension GRPCCore.ServiceDescriptor {
          /// Service descriptor for the "test.TestService" service.
          \(access) static let test_TestService = GRPCCore.ServiceDescriptor(fullyQualifiedService: "test.TestService")
        }

        // MARK: test.TestService (server)

        extension Test_TestService {
          /// Streaming variant of the service protocol for the "test.TestService" service.
          ///
          /// This protocol is the lowest-level of the service protocols generated for this service
          /// giving you the most flexibility over the implementation of your service. This comes at
          /// the cost of more verbose and less strict APIs. Each RPC requires you to implement it in
          /// terms of a request stream and response stream. Where only a single request or response
          /// message is expected, you are responsible for enforcing this invariant is maintained.
          ///
          /// Where possible, prefer using the stricter, less-verbose ``ServiceProtocol``
          /// or ``SimpleServiceProtocol`` instead.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Service docs.
          \(access) protocol StreamingServiceProtocol: GRPCCore.RegistrableRPCService {
            /// Handle the "Unary" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Unary docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request of `Test_TestInput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A streaming response of `Test_TestOutput` messages.
            func unary(
              request: GRPCCore.StreamingServerRequest<Test_TestInput>,
              context: GRPCCore.ServerContext
            ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput>

            /// Handle the "ClientStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Client streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request of `Test_TestInput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A streaming response of `Test_TestOutput` messages.
            func clientStreaming(
              request: GRPCCore.StreamingServerRequest<Test_TestInput>,
              context: GRPCCore.ServerContext
            ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput>

            /// Handle the "ServerStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Server streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request of `Test_TestInput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A streaming response of `Test_TestOutput` messages.
            func serverStreaming(
              request: GRPCCore.StreamingServerRequest<Test_TestInput>,
              context: GRPCCore.ServerContext
            ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput>

            /// Handle the "BidirectionalStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Bidirectional streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request of `Test_TestInput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A streaming response of `Test_TestOutput` messages.
            func bidirectionalStreaming(
              request: GRPCCore.StreamingServerRequest<Test_TestInput>,
              context: GRPCCore.ServerContext
            ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput>
          }

          /// Service protocol for the "test.TestService" service.
          ///
          /// This protocol is higher level than ``StreamingServiceProtocol`` but lower level than
          /// the ``SimpleServiceProtocol``, it provides access to request and response metadata and
          /// trailing response metadata. If you don't need these then consider using
          /// the ``SimpleServiceProtocol``. If you need fine grained control over your RPCs then
          /// use ``StreamingServiceProtocol``.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Service docs.
          \(access) protocol ServiceProtocol: Test_TestService.StreamingServiceProtocol {
            /// Handle the "Unary" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Unary docs.
            ///
            /// - Parameters:
            ///   - request: A request containing a single `Test_TestInput` message.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A response containing a single `Test_TestOutput` message.
            func unary(
              request: GRPCCore.ServerRequest<Test_TestInput>,
              context: GRPCCore.ServerContext
            ) async throws -> GRPCCore.ServerResponse<Test_TestOutput>

            /// Handle the "ClientStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Client streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request of `Test_TestInput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A response containing a single `Test_TestOutput` message.
            func clientStreaming(
              request: GRPCCore.StreamingServerRequest<Test_TestInput>,
              context: GRPCCore.ServerContext
            ) async throws -> GRPCCore.ServerResponse<Test_TestOutput>

            /// Handle the "ServerStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Server streaming docs.
            ///
            /// - Parameters:
            ///   - request: A request containing a single `Test_TestInput` message.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A streaming response of `Test_TestOutput` messages.
            func serverStreaming(
              request: GRPCCore.ServerRequest<Test_TestInput>,
              context: GRPCCore.ServerContext
            ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput>

            /// Handle the "BidirectionalStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Bidirectional streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request of `Test_TestInput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A streaming response of `Test_TestOutput` messages.
            func bidirectionalStreaming(
              request: GRPCCore.StreamingServerRequest<Test_TestInput>,
              context: GRPCCore.ServerContext
            ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput>
          }

          /// Simple service protocol for the "test.TestService" service.
          ///
          /// This is the highest level protocol for the service. The API is the easiest to use but
          /// doesn't provide access to request or response metadata. If you need access to these
          /// then use ``ServiceProtocol`` instead.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Service docs.
          \(access) protocol SimpleServiceProtocol: Test_TestService.ServiceProtocol {
            /// Handle the "Unary" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Unary docs.
            ///
            /// - Parameters:
            ///   - request: A `Test_TestInput` message.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A `Test_TestOutput` to respond with.
            func unary(
              request: Test_TestInput,
              context: GRPCCore.ServerContext
            ) async throws -> Test_TestOutput

            /// Handle the "ClientStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Client streaming docs.
            ///
            /// - Parameters:
            ///   - request: A stream of `Test_TestInput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            /// - Returns: A `Test_TestOutput` to respond with.
            func clientStreaming(
              request: GRPCCore.RPCAsyncSequence<Test_TestInput, any Swift.Error>,
              context: GRPCCore.ServerContext
            ) async throws -> Test_TestOutput

            /// Handle the "ServerStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Server streaming docs.
            ///
            /// - Parameters:
            ///   - request: A `Test_TestInput` message.
            ///   - response: A response stream of `Test_TestOutput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            func serverStreaming(
              request: Test_TestInput,
              response: GRPCCore.RPCWriter<Test_TestOutput>,
              context: GRPCCore.ServerContext
            ) async throws

            /// Handle the "BidirectionalStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Bidirectional streaming docs.
            ///
            /// - Parameters:
            ///   - request: A stream of `Test_TestInput` messages.
            ///   - response: A response stream of `Test_TestOutput` messages.
            ///   - context: Context providing information about the RPC.
            /// - Throws: Any error which occurred during the processing of the request. Thrown errors
            ///     of type `RPCError` are mapped to appropriate statuses. All other errors are converted
            ///     to an internal error.
            func bidirectionalStreaming(
              request: GRPCCore.RPCAsyncSequence<Test_TestInput, any Swift.Error>,
              response: GRPCCore.RPCWriter<Test_TestOutput>,
              context: GRPCCore.ServerContext
            ) async throws
          }
        }

        // Default implementation of 'registerMethods(with:)'.
        extension Test_TestService.StreamingServiceProtocol {
          \(access) func registerMethods<Transport>(with router: inout GRPCCore.RPCRouter<Transport>) where Transport: GRPCCore.ServerTransport {
            router.registerHandler(
              forMethod: Test_TestService.Method.Unary.descriptor,
              deserializer: GRPCProtobuf.ProtobufDeserializer<Test_TestInput>(),
              serializer: GRPCProtobuf.ProtobufSerializer<Test_TestOutput>(),
              handler: { request, context in
                try await self.unary(
                  request: request,
                  context: context
                )
              }
            )
            router.registerHandler(
              forMethod: Test_TestService.Method.ClientStreaming.descriptor,
              deserializer: GRPCProtobuf.ProtobufDeserializer<Test_TestInput>(),
              serializer: GRPCProtobuf.ProtobufSerializer<Test_TestOutput>(),
              handler: { request, context in
                try await self.clientStreaming(
                  request: request,
                  context: context
                )
              }
            )
            router.registerHandler(
              forMethod: Test_TestService.Method.ServerStreaming.descriptor,
              deserializer: GRPCProtobuf.ProtobufDeserializer<Test_TestInput>(),
              serializer: GRPCProtobuf.ProtobufSerializer<Test_TestOutput>(),
              handler: { request, context in
                try await self.serverStreaming(
                  request: request,
                  context: context
                )
              }
            )
            router.registerHandler(
              forMethod: Test_TestService.Method.BidirectionalStreaming.descriptor,
              deserializer: GRPCProtobuf.ProtobufDeserializer<Test_TestInput>(),
              serializer: GRPCProtobuf.ProtobufSerializer<Test_TestOutput>(),
              handler: { request, context in
                try await self.bidirectionalStreaming(
                  request: request,
                  context: context
                )
              }
            )
          }
        }

        // Default implementation of streaming methods from 'StreamingServiceProtocol'.
        extension Test_TestService.ServiceProtocol {
          \(access) func unary(
            request: GRPCCore.StreamingServerRequest<Test_TestInput>,
            context: GRPCCore.ServerContext
          ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput> {
            let response = try await self.unary(
              request: GRPCCore.ServerRequest(stream: request),
              context: context
            )
            return GRPCCore.StreamingServerResponse(single: response)
          }

          \(access) func clientStreaming(
            request: GRPCCore.StreamingServerRequest<Test_TestInput>,
            context: GRPCCore.ServerContext
          ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput> {
            let response = try await self.clientStreaming(
              request: request,
              context: context
            )
            return GRPCCore.StreamingServerResponse(single: response)
          }

          \(access) func serverStreaming(
            request: GRPCCore.StreamingServerRequest<Test_TestInput>,
            context: GRPCCore.ServerContext
          ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput> {
            let response = try await self.serverStreaming(
              request: GRPCCore.ServerRequest(stream: request),
              context: context
            )
            return response
          }
        }

        // Default implementation of methods from 'ServiceProtocol'.
        extension Test_TestService.SimpleServiceProtocol {
          \(access) func unary(
            request: GRPCCore.ServerRequest<Test_TestInput>,
            context: GRPCCore.ServerContext
          ) async throws -> GRPCCore.ServerResponse<Test_TestOutput> {
            return GRPCCore.ServerResponse<Test_TestOutput>(
              message: try await self.unary(
                request: request.message,
                context: context
              ),
              metadata: [:]
            )
          }

          \(access) func clientStreaming(
            request: GRPCCore.StreamingServerRequest<Test_TestInput>,
            context: GRPCCore.ServerContext
          ) async throws -> GRPCCore.ServerResponse<Test_TestOutput> {
            return GRPCCore.ServerResponse<Test_TestOutput>(
              message: try await self.clientStreaming(
                request: request.messages,
                context: context
              ),
              metadata: [:]
            )
          }

          \(access) func serverStreaming(
            request: GRPCCore.ServerRequest<Test_TestInput>,
            context: GRPCCore.ServerContext
          ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput> {
            return GRPCCore.StreamingServerResponse<Test_TestOutput>(
              metadata: [:],
              producer: { writer in
                try await self.serverStreaming(
                  request: request.message,
                  response: writer,
                  context: context
                )
                return [:]
              }
            )
          }

          \(access) func bidirectionalStreaming(
            request: GRPCCore.StreamingServerRequest<Test_TestInput>,
            context: GRPCCore.ServerContext
          ) async throws -> GRPCCore.StreamingServerResponse<Test_TestOutput> {
            return GRPCCore.StreamingServerResponse<Test_TestOutput>(
              metadata: [:],
              producer: { writer in
                try await self.bidirectionalStreaming(
                  request: request.messages,
                  response: writer,
                  context: context
                )
                return [:]
              }
            )
          }
        }

        // MARK: test.TestService (client)

        extension Test_TestService {
          /// Generated client protocol for the "test.TestService" service.
          ///
          /// You don't need to implement this protocol directly, use the generated
          /// implementation, ``Client``.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Service docs.
          \(access) protocol ClientProtocol: Sendable {
            /// Call the "Unary" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Unary docs.
            ///
            /// - Parameters:
            ///   - request: A request containing a single `Test_TestInput` message.
            ///   - serializer: A serializer for `Test_TestInput` messages.
            ///   - deserializer: A deserializer for `Test_TestOutput` messages.
            ///   - options: Options to apply to this RPC.
            ///   - handleResponse: A closure which handles the response, the result of which is
            ///       returned to the caller. Returning from the closure will cancel the RPC if it
            ///       hasn't already finished.
            /// - Returns: The result of `handleResponse`.
            func unary<Result>(
              request: GRPCCore.ClientRequest<Test_TestInput>,
              serializer: some GRPCCore.MessageSerializer<Test_TestInput>,
              deserializer: some GRPCCore.MessageDeserializer<Test_TestOutput>,
              options: GRPCCore.CallOptions,
              onResponse handleResponse: @Sendable @escaping (GRPCCore.ClientResponse<Test_TestOutput>) async throws -> Result
            ) async throws -> Result where Result: Sendable

            /// Call the "ClientStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Client streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request producing `Test_TestInput` messages.
            ///   - serializer: A serializer for `Test_TestInput` messages.
            ///   - deserializer: A deserializer for `Test_TestOutput` messages.
            ///   - options: Options to apply to this RPC.
            ///   - handleResponse: A closure which handles the response, the result of which is
            ///       returned to the caller. Returning from the closure will cancel the RPC if it
            ///       hasn't already finished.
            /// - Returns: The result of `handleResponse`.
            func clientStreaming<Result>(
              request: GRPCCore.StreamingClientRequest<Test_TestInput>,
              serializer: some GRPCCore.MessageSerializer<Test_TestInput>,
              deserializer: some GRPCCore.MessageDeserializer<Test_TestOutput>,
              options: GRPCCore.CallOptions,
              onResponse handleResponse: @Sendable @escaping (GRPCCore.ClientResponse<Test_TestOutput>) async throws -> Result
            ) async throws -> Result where Result: Sendable

            /// Call the "ServerStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Server streaming docs.
            ///
            /// - Parameters:
            ///   - request: A request containing a single `Test_TestInput` message.
            ///   - serializer: A serializer for `Test_TestInput` messages.
            ///   - deserializer: A deserializer for `Test_TestOutput` messages.
            ///   - options: Options to apply to this RPC.
            ///   - handleResponse: A closure which handles the response, the result of which is
            ///       returned to the caller. Returning from the closure will cancel the RPC if it
            ///       hasn't already finished.
            /// - Returns: The result of `handleResponse`.
            func serverStreaming<Result>(
              request: GRPCCore.ClientRequest<Test_TestInput>,
              serializer: some GRPCCore.MessageSerializer<Test_TestInput>,
              deserializer: some GRPCCore.MessageDeserializer<Test_TestOutput>,
              options: GRPCCore.CallOptions,
              onResponse handleResponse: @Sendable @escaping (GRPCCore.StreamingClientResponse<Test_TestOutput>) async throws -> Result
            ) async throws -> Result where Result: Sendable

            /// Call the "BidirectionalStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Bidirectional streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request producing `Test_TestInput` messages.
            ///   - serializer: A serializer for `Test_TestInput` messages.
            ///   - deserializer: A deserializer for `Test_TestOutput` messages.
            ///   - options: Options to apply to this RPC.
            ///   - handleResponse: A closure which handles the response, the result of which is
            ///       returned to the caller. Returning from the closure will cancel the RPC if it
            ///       hasn't already finished.
            /// - Returns: The result of `handleResponse`.
            func bidirectionalStreaming<Result>(
              request: GRPCCore.StreamingClientRequest<Test_TestInput>,
              serializer: some GRPCCore.MessageSerializer<Test_TestInput>,
              deserializer: some GRPCCore.MessageDeserializer<Test_TestOutput>,
              options: GRPCCore.CallOptions,
              onResponse handleResponse: @Sendable @escaping (GRPCCore.StreamingClientResponse<Test_TestOutput>) async throws -> Result
            ) async throws -> Result where Result: Sendable
          }

          /// Generated client for the "test.TestService" service.
          ///
          /// The ``Client`` provides an implementation of ``ClientProtocol`` which wraps
          /// a `GRPCCore.GRPCCClient`. The underlying `GRPCClient` provides the long-lived
          /// means of communication with the remote peer.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Service docs.
          \(access) struct Client<Transport>: ClientProtocol where Transport: GRPCCore.ClientTransport {
            private let client: GRPCCore.GRPCClient<Transport>

            /// Creates a new client wrapping the provided `GRPCCore.GRPCClient`.
            ///
            /// - Parameters:
            ///   - client: A `GRPCCore.GRPCClient` providing a communication channel to the service.
            \(access) init(wrapping client: GRPCCore.GRPCClient<Transport>) {
              self.client = client
            }

            /// Call the "Unary" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Unary docs.
            ///
            /// - Parameters:
            ///   - request: A request containing a single `Test_TestInput` message.
            ///   - serializer: A serializer for `Test_TestInput` messages.
            ///   - deserializer: A deserializer for `Test_TestOutput` messages.
            ///   - options: Options to apply to this RPC.
            ///   - handleResponse: A closure which handles the response, the result of which is
            ///       returned to the caller. Returning from the closure will cancel the RPC if it
            ///       hasn't already finished.
            /// - Returns: The result of `handleResponse`.
            \(access) func unary<Result>(
              request: GRPCCore.ClientRequest<Test_TestInput>,
              serializer: some GRPCCore.MessageSerializer<Test_TestInput>,
              deserializer: some GRPCCore.MessageDeserializer<Test_TestOutput>,
              options: GRPCCore.CallOptions = .defaults,
              onResponse handleResponse: @Sendable @escaping (GRPCCore.ClientResponse<Test_TestOutput>) async throws -> Result = { response in
                try response.message
              }
            ) async throws -> Result where Result: Sendable {
              try await self.client.unary(
                request: request,
                descriptor: Test_TestService.Method.Unary.descriptor,
                serializer: serializer,
                deserializer: deserializer,
                options: options,
                onResponse: handleResponse
              )
            }

            /// Call the "ClientStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Client streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request producing `Test_TestInput` messages.
            ///   - serializer: A serializer for `Test_TestInput` messages.
            ///   - deserializer: A deserializer for `Test_TestOutput` messages.
            ///   - options: Options to apply to this RPC.
            ///   - handleResponse: A closure which handles the response, the result of which is
            ///       returned to the caller. Returning from the closure will cancel the RPC if it
            ///       hasn't already finished.
            /// - Returns: The result of `handleResponse`.
            \(access) func clientStreaming<Result>(
              request: GRPCCore.StreamingClientRequest<Test_TestInput>,
              serializer: some GRPCCore.MessageSerializer<Test_TestInput>,
              deserializer: some GRPCCore.MessageDeserializer<Test_TestOutput>,
              options: GRPCCore.CallOptions = .defaults,
              onResponse handleResponse: @Sendable @escaping (GRPCCore.ClientResponse<Test_TestOutput>) async throws -> Result = { response in
                try response.message
              }
            ) async throws -> Result where Result: Sendable {
              try await self.client.clientStreaming(
                request: request,
                descriptor: Test_TestService.Method.ClientStreaming.descriptor,
                serializer: serializer,
                deserializer: deserializer,
                options: options,
                onResponse: handleResponse
              )
            }

            /// Call the "ServerStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Server streaming docs.
            ///
            /// - Parameters:
            ///   - request: A request containing a single `Test_TestInput` message.
            ///   - serializer: A serializer for `Test_TestInput` messages.
            ///   - deserializer: A deserializer for `Test_TestOutput` messages.
            ///   - options: Options to apply to this RPC.
            ///   - handleResponse: A closure which handles the response, the result of which is
            ///       returned to the caller. Returning from the closure will cancel the RPC if it
            ///       hasn't already finished.
            /// - Returns: The result of `handleResponse`.
            \(access) func serverStreaming<Result>(
              request: GRPCCore.ClientRequest<Test_TestInput>,
              serializer: some GRPCCore.MessageSerializer<Test_TestInput>,
              deserializer: some GRPCCore.MessageDeserializer<Test_TestOutput>,
              options: GRPCCore.CallOptions = .defaults,
              onResponse handleResponse: @Sendable @escaping (GRPCCore.StreamingClientResponse<Test_TestOutput>) async throws -> Result
            ) async throws -> Result where Result: Sendable {
              try await self.client.serverStreaming(
                request: request,
                descriptor: Test_TestService.Method.ServerStreaming.descriptor,
                serializer: serializer,
                deserializer: deserializer,
                options: options,
                onResponse: handleResponse
              )
            }

            /// Call the "BidirectionalStreaming" method.
            ///
            /// > Source IDL Documentation:
            /// >
            /// > Bidirectional streaming docs.
            ///
            /// - Parameters:
            ///   - request: A streaming request producing `Test_TestInput` messages.
            ///   - serializer: A serializer for `Test_TestInput` messages.
            ///   - deserializer: A deserializer for `Test_TestOutput` messages.
            ///   - options: Options to apply to this RPC.
            ///   - handleResponse: A closure which handles the response, the result of which is
            ///       returned to the caller. Returning from the closure will cancel the RPC if it
            ///       hasn't already finished.
            /// - Returns: The result of `handleResponse`.
            \(access) func bidirectionalStreaming<Result>(
              request: GRPCCore.StreamingClientRequest<Test_TestInput>,
              serializer: some GRPCCore.MessageSerializer<Test_TestInput>,
              deserializer: some GRPCCore.MessageDeserializer<Test_TestOutput>,
              options: GRPCCore.CallOptions = .defaults,
              onResponse handleResponse: @Sendable @escaping (GRPCCore.StreamingClientResponse<Test_TestOutput>) async throws -> Result
            ) async throws -> Result where Result: Sendable {
              try await self.client.bidirectionalStreaming(
                request: request,
                descriptor: Test_TestService.Method.BidirectionalStreaming.descriptor,
                serializer: serializer,
                deserializer: deserializer,
                options: options,
                onResponse: handleResponse
              )
            }
          }
        }

        // Helpers providing default arguments to 'ClientProtocol' methods.
        extension Test_TestService.ClientProtocol {
          /// Call the "Unary" method.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Unary docs.
          ///
          /// - Parameters:
          ///   - request: A request containing a single `Test_TestInput` message.
          ///   - options: Options to apply to this RPC.
          ///   - handleResponse: A closure which handles the response, the result of which is
          ///       returned to the caller. Returning from the closure will cancel the RPC if it
          ///       hasn't already finished.
          /// - Returns: The result of `handleResponse`.
          \(access) func unary<Result>(
            request: GRPCCore.ClientRequest<Test_TestInput>,
            options: GRPCCore.CallOptions = .defaults,
            onResponse handleResponse: @Sendable @escaping (GRPCCore.ClientResponse<Test_TestOutput>) async throws -> Result = { response in
              try response.message
            }
          ) async throws -> Result where Result: Sendable {
            try await self.unary(
              request: request,
              serializer: GRPCProtobuf.ProtobufSerializer<Test_TestInput>(),
              deserializer: GRPCProtobuf.ProtobufDeserializer<Test_TestOutput>(),
              options: options,
              onResponse: handleResponse
            )
          }

          /// Call the "ClientStreaming" method.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Client streaming docs.
          ///
          /// - Parameters:
          ///   - request: A streaming request producing `Test_TestInput` messages.
          ///   - options: Options to apply to this RPC.
          ///   - handleResponse: A closure which handles the response, the result of which is
          ///       returned to the caller. Returning from the closure will cancel the RPC if it
          ///       hasn't already finished.
          /// - Returns: The result of `handleResponse`.
          \(access) func clientStreaming<Result>(
            request: GRPCCore.StreamingClientRequest<Test_TestInput>,
            options: GRPCCore.CallOptions = .defaults,
            onResponse handleResponse: @Sendable @escaping (GRPCCore.ClientResponse<Test_TestOutput>) async throws -> Result = { response in
              try response.message
            }
          ) async throws -> Result where Result: Sendable {
            try await self.clientStreaming(
              request: request,
              serializer: GRPCProtobuf.ProtobufSerializer<Test_TestInput>(),
              deserializer: GRPCProtobuf.ProtobufDeserializer<Test_TestOutput>(),
              options: options,
              onResponse: handleResponse
            )
          }

          /// Call the "ServerStreaming" method.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Server streaming docs.
          ///
          /// - Parameters:
          ///   - request: A request containing a single `Test_TestInput` message.
          ///   - options: Options to apply to this RPC.
          ///   - handleResponse: A closure which handles the response, the result of which is
          ///       returned to the caller. Returning from the closure will cancel the RPC if it
          ///       hasn't already finished.
          /// - Returns: The result of `handleResponse`.
          \(access) func serverStreaming<Result>(
            request: GRPCCore.ClientRequest<Test_TestInput>,
            options: GRPCCore.CallOptions = .defaults,
            onResponse handleResponse: @Sendable @escaping (GRPCCore.StreamingClientResponse<Test_TestOutput>) async throws -> Result
          ) async throws -> Result where Result: Sendable {
            try await self.serverStreaming(
              request: request,
              serializer: GRPCProtobuf.ProtobufSerializer<Test_TestInput>(),
              deserializer: GRPCProtobuf.ProtobufDeserializer<Test_TestOutput>(),
              options: options,
              onResponse: handleResponse
            )
          }

          /// Call the "BidirectionalStreaming" method.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Bidirectional streaming docs.
          ///
          /// - Parameters:
          ///   - request: A streaming request producing `Test_TestInput` messages.
          ///   - options: Options to apply to this RPC.
          ///   - handleResponse: A closure which handles the response, the result of which is
          ///       returned to the caller. Returning from the closure will cancel the RPC if it
          ///       hasn't already finished.
          /// - Returns: The result of `handleResponse`.
          \(access) func bidirectionalStreaming<Result>(
            request: GRPCCore.StreamingClientRequest<Test_TestInput>,
            options: GRPCCore.CallOptions = .defaults,
            onResponse handleResponse: @Sendable @escaping (GRPCCore.StreamingClientResponse<Test_TestOutput>) async throws -> Result
          ) async throws -> Result where Result: Sendable {
            try await self.bidirectionalStreaming(
              request: request,
              serializer: GRPCProtobuf.ProtobufSerializer<Test_TestInput>(),
              deserializer: GRPCProtobuf.ProtobufDeserializer<Test_TestOutput>(),
              options: options,
              onResponse: handleResponse
            )
          }
        }

        // Helpers providing sugared APIs for 'ClientProtocol' methods.
        extension Test_TestService.ClientProtocol {
          /// Call the "Unary" method.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Unary docs.
          ///
          /// - Parameters:
          ///   - message: request message to send.
          ///   - metadata: Additional metadata to send, defaults to empty.
          ///   - options: Options to apply to this RPC, defaults to `.defaults`.
          ///   - handleResponse: A closure which handles the response, the result of which is
          ///       returned to the caller. Returning from the closure will cancel the RPC if it
          ///       hasn't already finished.
          /// - Returns: The result of `handleResponse`.
          \(access) func unary<Result>(
            _ message: Test_TestInput,
            metadata: GRPCCore.Metadata = [:],
            options: GRPCCore.CallOptions = .defaults,
            onResponse handleResponse: @Sendable @escaping (GRPCCore.ClientResponse<Test_TestOutput>) async throws -> Result = { response in
              try response.message
            }
          ) async throws -> Result where Result: Sendable {
            let request = GRPCCore.ClientRequest<Test_TestInput>(
              message: message,
              metadata: metadata
            )
            return try await self.unary(
              request: request,
              options: options,
              onResponse: handleResponse
            )
          }

          /// Call the "ClientStreaming" method.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Client streaming docs.
          ///
          /// - Parameters:
          ///   - metadata: Additional metadata to send, defaults to empty.
          ///   - options: Options to apply to this RPC, defaults to `.defaults`.
          ///   - producer: A closure producing request messages to send to the server. The request
          ///       stream is closed when the closure returns.
          ///   - handleResponse: A closure which handles the response, the result of which is
          ///       returned to the caller. Returning from the closure will cancel the RPC if it
          ///       hasn't already finished.
          /// - Returns: The result of `handleResponse`.
          \(access) func clientStreaming<Result>(
            metadata: GRPCCore.Metadata = [:],
            options: GRPCCore.CallOptions = .defaults,
            requestProducer producer: @Sendable @escaping (GRPCCore.RPCWriter<Test_TestInput>) async throws -> Void,
            onResponse handleResponse: @Sendable @escaping (GRPCCore.ClientResponse<Test_TestOutput>) async throws -> Result = { response in
              try response.message
            }
          ) async throws -> Result where Result: Sendable {
            let request = GRPCCore.StreamingClientRequest<Test_TestInput>(
              metadata: metadata,
              producer: producer
            )
            return try await self.clientStreaming(
              request: request,
              options: options,
              onResponse: handleResponse
            )
          }

          /// Call the "ServerStreaming" method.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Server streaming docs.
          ///
          /// - Parameters:
          ///   - message: request message to send.
          ///   - metadata: Additional metadata to send, defaults to empty.
          ///   - options: Options to apply to this RPC, defaults to `.defaults`.
          ///   - handleResponse: A closure which handles the response, the result of which is
          ///       returned to the caller. Returning from the closure will cancel the RPC if it
          ///       hasn't already finished.
          /// - Returns: The result of `handleResponse`.
          \(access) func serverStreaming<Result>(
            _ message: Test_TestInput,
            metadata: GRPCCore.Metadata = [:],
            options: GRPCCore.CallOptions = .defaults,
            onResponse handleResponse: @Sendable @escaping (GRPCCore.StreamingClientResponse<Test_TestOutput>) async throws -> Result
          ) async throws -> Result where Result: Sendable {
            let request = GRPCCore.ClientRequest<Test_TestInput>(
              message: message,
              metadata: metadata
            )
            return try await self.serverStreaming(
              request: request,
              options: options,
              onResponse: handleResponse
            )
          }

          /// Call the "BidirectionalStreaming" method.
          ///
          /// > Source IDL Documentation:
          /// >
          /// > Bidirectional streaming docs.
          ///
          /// - Parameters:
          ///   - metadata: Additional metadata to send, defaults to empty.
          ///   - options: Options to apply to this RPC, defaults to `.defaults`.
          ///   - producer: A closure producing request messages to send to the server. The request
          ///       stream is closed when the closure returns.
          ///   - handleResponse: A closure which handles the response, the result of which is
          ///       returned to the caller. Returning from the closure will cancel the RPC if it
          ///       hasn't already finished.
          /// - Returns: The result of `handleResponse`.
          \(access) func bidirectionalStreaming<Result>(
            metadata: GRPCCore.Metadata = [:],
            options: GRPCCore.CallOptions = .defaults,
            requestProducer producer: @Sendable @escaping (GRPCCore.RPCWriter<Test_TestInput>) async throws -> Void,
            onResponse handleResponse: @Sendable @escaping (GRPCCore.StreamingClientResponse<Test_TestOutput>) async throws -> Result
          ) async throws -> Result where Result: Sendable {
            let request = GRPCCore.StreamingClientRequest<Test_TestInput>(
              metadata: metadata,
              producer: producer
            )
            return try await self.bidirectionalStreaming(
              request: request,
              options: options,
              onResponse: handleResponse
            )
          }
        }
        """

      #expect(generated == expected)
    }
  }

  @Suite("File-without-services (foo-messages.proto)")
  struct NoServices: UsesDescriptorSet {
    static let descriptorSetName = "foo-messages"
    static let fileDescriptorName = "foo-messages"

    @Test("Generate")
    func generate() throws {
      let generator = ProtobufCodeGenerator(
        config: CodeGenerator.Config(
          accessLevel: .public,
          accessLevelOnImports: false,
          client: true,
          server: true,
          indentation: 2
        )
      )

      let generated = try generator.generateCode(
        fileDescriptor: Self.fileDescriptor,
        protoFileModuleMappings: ProtoFileToModuleMappings(),
        extraModuleImports: []
      )

      let expected = """
        /// Leading trivia.

        // DO NOT EDIT.
        // swift-format-ignore-file
        //
        // Generated by the gRPC Swift generator plugin for the protocol buffer compiler.
        // Source: foo-messages.proto
        //
        // For information on using the generated types, please see the documentation:
        //   https://github.com/grpc/grpc-swift

        // This file contained no services.
        """

      #expect(generated == expected)
    }
  }
}