Unit tests for interop tests (#1823)

Motivation:

We need unit tests that run the interop tests with the in process transport.

Modifications:

Created a test target and implemented the tests for each interop test, that catch AssertionFailure
errors when the interop tests fail.

Result:

We will run the interop tests with the in process transport.

Package.swift

@@ -361,6 +361,15 @@ extension Target {
     ]
   )
 
+  static let inProcessInteroperabilityTests: Target = .testTarget(
+    name: "InProcessInteroperabilityTests",
+    dependencies: [
+      .grpcInProcessTransport,
+      .interoperabilityTests,
+      .grpcCore
+    ]
+  )
+  
   static let interopTestModels: Target = .target(
     name: "GRPCInteroperabilityTestModels",
     dependencies: [
@@ -724,6 +733,7 @@ let package = Package(
     .grpcHTTP2TransportNIOTransportServicesTests,
     .grpcProtobufTests,
     .grpcProtobufCodeGenTests,
+    .inProcessInteroperabilityTests
   ]
 )
 

Sources/InteroperabilityTests/InteroperabilityTestCase.swift

@@ -66,7 +66,7 @@ public enum InteroperabilityTestCase: String, CaseIterable {
   }
 }
 
-@available(macOS 13.0, *)
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
 extension InteroperabilityTestCase {
   /// Return a new instance of the test case.
   public func makeTest() -> InteroperabilityTest {

Tests/InProcessInteroperabilityTests/InProcessInteroperabilityTests.swift

@@ -0,0 +1,99 @@
+/*
+ * 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 GRPCCore
+import GRPCInProcessTransport
+import XCTest
+
+@testable import InteroperabilityTests
+
+@available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
+final class InProcessInteroperabilityTests: XCTestCase {
+  func runInProcessTransport(
+    interopTestCase: InteroperabilityTestCase
+  ) async throws {
+    do {
+      let inProcess = InProcessTransport.makePair()
+      try await withThrowingTaskGroup(of: Void.self) { group in
+        group.addTask {
+          let server = GRPCServer(transports: [inProcess.server], services: [TestService()])
+          try await server.run()
+        }
+
+        group.addTask {
+          try await withThrowingTaskGroup(of: Void.self) { clientGroup in
+            let client = GRPCClient(transport: inProcess.client)
+            clientGroup.addTask {
+              try await client.run()
+            }
+            try await interopTestCase.makeTest().run(client: client)
+
+            clientGroup.cancelAll()
+          }
+        }
+
+        try await group.next()
+        group.cancelAll()
+      }
+    } catch let error as AssertionFailure {
+      XCTFail(error.message)
+    }
+  }
+
+  func testEmtyUnary() async throws {
+    try await self.runInProcessTransport(interopTestCase: .emptyUnary)
+  }
+
+  func testLargeUnary() async throws {
+    try await self.runInProcessTransport(interopTestCase: .largeUnary)
+  }
+
+  func testClientStreaming() async throws {
+    try await self.runInProcessTransport(interopTestCase: .clientStreaming)
+  }
+
+  func testServerStreaming() async throws {
+    try await self.runInProcessTransport(interopTestCase: .serverStreaming)
+  }
+
+  func testPingPong() async throws {
+    try await self.runInProcessTransport(interopTestCase: .pingPong)
+  }
+
+  func testEmptyStream() async throws {
+    try await self.runInProcessTransport(interopTestCase: .emptyStream)
+  }
+
+  func testCustomMetdata() async throws {
+    try await self.runInProcessTransport(interopTestCase: .customMetadata)
+  }
+
+  func testStatusCodeAndMessage() async throws {
+    try await self.runInProcessTransport(interopTestCase: .statusCodeAndMessage)
+  }
+
+  func testSpecialStatusMessage() async throws {
+    try await self.runInProcessTransport(interopTestCase: .specialStatusMessage)
+  }
+
+  func testUnimplementedMethod() async throws {
+    try await self.runInProcessTransport(interopTestCase: .unimplementedMethod)
+  }
+
+  func testUnimplementedService() async throws {
+    try await self.runInProcessTransport(interopTestCase: .unimplementedService)
+  }
+}