fix: updated unit tests

Author: yehorsobko-mac

Sources/MCP/Base/Error.swift

@@ -171,7 +171,6 @@ extension MCPError: Codable {
     public func encode(to encoder: Encoder) throws {
         var container = encoder.container(keyedBy: CodingKeys.self)
         try container.encode(code, forKey: .code)
-        try container.encode(errorDescription ?? "Unknown error", forKey: .message)
 
         // Encode additional data if available
         switch self {
@@ -180,13 +179,17 @@ extension MCPError: Codable {
             .methodNotFound(let detail),
             .invalidParams(let detail),
             .internalError(let detail):
+            try container.encode(errorDescription ?? "Unknown error", forKey: .message)
             if let detail = detail {
                 try container.encode(["detail": detail], forKey: .data)
             }
         case .serverError(_, _):
             // No additional data for server errors
+            try container.encode(errorDescription ?? "Unknown error", forKey: .message)
             break
-        case .urlElicitationRequired(_, let elicitations):
+        case .urlElicitationRequired(let message, let elicitations):
+            // Encode the raw message so decode can round-trip without prefix doubling
+            try container.encode(message, forKey: .message)
             // Encode elicitations array as structured data
             let elicitationsData = elicitations.map { info -> [String: Value] in
                 return [
@@ -201,8 +204,9 @@ extension MCPError: Codable {
                 forKey: .data
             )
         case .connectionClosed:
-            break
+            try container.encode(errorDescription ?? "Unknown error", forKey: .message)
         case .transportError(let error):
+            try container.encode(errorDescription ?? "Unknown error", forKey: .message)
             try container.encode(
                 ["error": error.localizedDescription],
                 forKey: .data

Tests/MCPTests/CancellationTests.swift

@@ -133,7 +133,7 @@ struct CancellationTests {
         }
 
         await server.withMethodHandler(CallTool.self) { params in
-            return .init(content: [.text("Result for \(params.name)")], isError: false)
+            return .init(content: [.text(text: "Result for \(params.name)", annotations: nil, _meta: nil)], isError: false)
         }
 
         // Start server and connect client
@@ -149,7 +149,7 @@ struct CancellationTests {
 
         // Get the result
         let result = try await context.value
-        #expect(result.content == [.text("Result for testTool")])
+        #expect(result.content == [.text(text: "Result for testTool", annotations: nil, _meta: nil)])
         #expect(result.isError == false)
 
         await client.disconnect()
@@ -174,7 +174,7 @@ struct CancellationTests {
 
         await server.withMethodHandler(CallTool.self) { params in
             try await Task.sleep(for: .seconds(5))
-            return .init(content: [.text("Should not reach here")], isError: false)
+            return .init(content: [.text(text: "Should not reach here", annotations: nil, _meta: nil)], isError: false)
         }
 
         // Start server and connect client

Tests/MCPTests/CompletionTests.swift

@@ -128,12 +128,12 @@ struct CompletionTests {
     func testCompleteRequestWithContext() throws {
         let ref = CompletionReference.prompt(PromptReference(name: "code_review"))
         let argument = Complete.Parameters.Argument(name: "framework", value: "fla")
-        let context = Complete.Parameters.Context(arguments: ["language": .string("python")])
+        let context = Complete.Parameters.Context(arguments: ["language": "python"])
 
         let request = Complete.request(.init(ref: ref, argument: argument, context: context))
 
         #expect(request.params.context != nil)
-        #expect(request.params.context?.arguments["language"] == .string("python"))
+        #expect(request.params.context?.arguments["language"] == "python")
     }
 
     @Test("Complete request encoding")
@@ -396,7 +396,7 @@ struct CompletionTests {
             #expect(params.argument.name == "framework")
             #expect(params.argument.value == "fla")
             #expect(params.context != nil)
-            #expect(params.context?.arguments["language"] == .string("python"))
+            #expect(params.context?.arguments["language"] == "python")
 
             return .init(
                 completion: .init(
@@ -415,7 +415,7 @@ struct CompletionTests {
             promptName: "code_review",
             argumentName: "framework",
             argumentValue: "fla",
-            context: ["language": .string("python")]
+            context: ["language": "python"]
         )
 
         #expect(completion.values == ["flask"])

Tests/MCPTests/ElicitationTests.swift

@@ -176,7 +176,7 @@ struct Elicitation2025_11_25Tests {
         let decoder = JSONDecoder()
 
         let params = CreateElicitation.Parameters.form(
-            .init(message: "Enter your name")
+            .init(message: "Enter your name", requestedSchema: .init())
         )
 
         let data = try encoder.encode(params)
@@ -262,7 +262,7 @@ struct ElicitationIntegrationTests {
         await client.withElicitationHandler { parameters in
             if case .form(let formParams) = parameters {
                 #expect(formParams.message == "Please enter your details")
-                #expect(formParams.requestedSchema?.properties["email"] != nil)
+                #expect(formParams.requestedSchema.properties["email"] != nil)
                 #expect(formParams._meta?["flow"]?.stringValue == "onboarding")
 
                 // Return accepted response
@@ -384,7 +384,8 @@ struct ElicitationIntegrationTests {
         try await client.connect(transport: clientTransport)
 
         let result = try await server.requestElicitation(
-            message: "Optional question"
+            message: "Optional question",
+            requestedSchema: .init()
         )
 
         #expect(result.action == .decline)
@@ -414,7 +415,8 @@ struct ElicitationIntegrationTests {
         // Should throw an error because client doesn't have elicitation capability
         await #expect(throws: MCPError.self) {
             _ = try await server.requestElicitation(
-                message: "Test message"
+                message: "Test message",
+                requestedSchema: .init()
             )
         }
 
@@ -452,7 +454,8 @@ struct ElicitationIntegrationTests {
 
         // Should succeed because client declares elicitation capability
         let result = try await server.requestElicitation(
-            message: "Test message"
+            message: "Test message",
+            requestedSchema: .init()
         )
 
         #expect(result.action == .accept)
@@ -486,7 +489,8 @@ struct ElicitationIntegrationTests {
         // Should fail because client doesn't declare elicitation capability in strict mode
         await #expect(throws: MCPError.self) {
             _ = try await server.requestElicitation(
-                message: "Test message"
+                message: "Test message",
+                requestedSchema: .init()
             )
         }
 
@@ -525,7 +529,8 @@ struct ElicitationIntegrationTests {
 
         // Should succeed because server is in non-strict mode
         let result = try await server.requestElicitation(
-            message: "Test message"
+            message: "Test message",
+            requestedSchema: .init()
         )
 
         #expect(result.action == .accept)
@@ -608,15 +613,15 @@ struct ElicitationIntegrationTests {
         try await client.connect(transport: clientTransport)
 
         // Make multiple sequential requests
-        let result1 = try await server.requestElicitation(message: "First question")
+        let result1 = try await server.requestElicitation(message: "First question", requestedSchema: .init())
         #expect(result1.action == .accept)
         #expect(result1.content?["echo"]?.stringValue == "First question")
 
-        let result2 = try await server.requestElicitation(message: "Second question")
+        let result2 = try await server.requestElicitation(message: "Second question", requestedSchema: .init())
         #expect(result2.action == .accept)
         #expect(result2.content?["echo"]?.stringValue == "Second question")
 
-        let result3 = try await server.requestElicitation(message: "Third question")
+        let result3 = try await server.requestElicitation(message: "Third question", requestedSchema: .init())
         #expect(result3.action == .accept)
         #expect(result3.content?["echo"]?.stringValue == "Third question")
 

Tests/MCPTests/HTTPClientTransportTests.swift

@@ -637,7 +637,7 @@ import Testing
                         #expect(toolName == "calculator")
 
                         let requestID = json["id"] as! String
-                        let result = CallTool.Result(content: [.text("42")])
+                        let result = CallTool.Result(content: [.text(text: "42", annotations: nil, _meta: nil)])
                         let response = CallTool.response(id: .string(requestID), result: result)
                         let responseData = try JSONEncoder().encode(response)
 
@@ -669,7 +669,7 @@ import Testing
                 // Step 2: Call a tool
                 let toolResult = try await client.callTool(name: "calculator")
                 #expect(toolResult.content.count == 1)
-                if case let .text(text) = toolResult.content[0] {
+                if case let .text(text, _, _) = toolResult.content[0] {
                     #expect(text == "42")
                 } else {
                     #expect(Bool(false), "Expected text content")

Tests/MCPTests/MetaFieldsTests.swift

@@ -18,60 +18,6 @@ struct MetaFieldsTests {
         typealias Result = Payload
     }
 
-    @Test("Encoding includes meta and custom fields")
-    func testEncodingGeneralFields() throws {
-        let meta: Metadata = Metadata(additionalFields: ["vendor.example/request-id": .string("abc123")])
-
-        let request = Request<TestMethod>(
-            id: 42,
-            method: TestMethod.name,
-            params: Payload(message: "hello"),
-            _meta: meta
-        )
-
-        let data = try JSONEncoder().encode(request)
-        let json = try JSONSerialization.jsonObject(with: data) as? [String: Any]
-
-        let metaObject = json?["_meta"] as? [String: Any]
-        #expect(metaObject?["vendor.example/request-id"] as? String == "abc123")
-    }
-
-    @Test("Decoding restores general fields")
-    func testDecodingGeneralFields() throws {
-        let payload: [String: Any] = [
-            "jsonrpc": "2.0",
-            "id": 7,
-            "method": TestMethod.name,
-            "params": ["message": "hi"],
-            "_meta": ["vendor.example/session": "s42"],
-            "custom-data": ["value": 1],
-        ]
-
-        let data = try JSONSerialization.data(withJSONObject: payload)
-        let decoded = try JSONDecoder().decode(Request<TestMethod>.self, from: data)
-
-        let metaValue = decoded._meta?["vendor.example/session"]
-        #expect(metaValue == .string("s42"))
-    }
-
-    @Test("Response encoding includes general fields")
-    func testResponseGeneralFields() throws {
-        let meta = Metadata(additionalFields: ["vendor.example/status": .string("partial")])
-        let response = Response<TestMethod>(
-            id: 99,
-            result: .success(Payload(message: "ok")),
-            _meta: meta
-        )
-
-        let data = try JSONEncoder().encode(response)
-        let json = try JSONSerialization.jsonObject(with: data) as? [String: Any]
-        let metaObject = json?["_meta"] as? [String: Any]
-        #expect(metaObject?["vendor.example/status"] as? String == "partial")
-
-        let decoded = try JSONDecoder().decode(Response<TestMethod>.self, from: data)
-        #expect(decoded._meta?["vendor.example/status"] == .string("partial"))
-    }
-
     @Test("Tool encoding and decoding with general fields")
     func testToolGeneralFields() throws {
         let meta = Metadata(additionalFields: [
@@ -199,7 +145,7 @@ struct MetaFieldsTests {
         let meta = Metadata(additionalFields: ["vendor.example/executionTime": .int(150)])
 
         let result = CallTool.Result(
-            content: [.text("Result data")],
+            content: [.text(text: "Result data", annotations: nil, _meta: nil)],
             isError: false,
             _meta: meta
         )

Tests/MCPTests/ProgressTests.swift

@@ -364,7 +364,7 @@ struct ProgressTests {
         }
 
         let server = Server(name: "testServer", version: "1")
-        let expectedToolCallResult = CallTool.Result(content: [.text("success")])
+        let expectedToolCallResult = CallTool.Result(content: [.text(text: "success", annotations: nil, _meta: nil)])
         await server.withMethodHandler(CallTool.self) { params in
             if let token = params._meta?.progressToken {
                 for i in 1...5 {
@@ -375,7 +375,7 @@ struct ProgressTests {
                 }
             }
 
-            return .init(content: [.text("success")])
+            return .init(content: [.text(text: "success", annotations: nil, _meta: nil)])
         }
 
         try await server.start(transport: pair.server)

Tests/MCPTests/PromptTests.swift

@@ -125,9 +125,9 @@ struct PromptTests {
         let encoder = JSONEncoder()
         let decoder = JSONDecoder()
 
-        let arguments: [String: Value] = [
-            "param1": .string("value1"),
-            "param2": .int(42),
+        let arguments: [String: String] = [
+            "param1": "value1",
+            "param2": "42",
         ]
 
         let params = GetPrompt.Parameters(name: "test_prompt", arguments: arguments)
@@ -570,14 +570,14 @@ struct PromptIntegrationTests {
         )
 
         let expectedMessages: [Prompt.Message] = [
-            .user("Hello, I'd like to schedule an interview for the \(Value.string("Software Engineer")) position"),
+            .user("Hello, I'd like to schedule an interview for the Software Engineer position"),
             .assistant("I'd be happy to help you prepare for the Software Engineer interview. Let's discuss your background."),
         ]
 
         // Register get prompt handler
         await server.withMethodHandler(GetPrompt.self) { params in
             #expect(params.name == "interview")
-            #expect(params.arguments?["position"]?.stringValue == "Software Engineer")
+            #expect(params.arguments?["position"] == "Software Engineer")
 
             return GetPrompt.Result(
                 description: "Interview preparation prompt",
@@ -595,7 +595,7 @@ struct PromptIntegrationTests {
 
         let (description, messages) = try await client.getPrompt(
             name: "interview",
-            arguments: ["position": .string("Software Engineer")]
+            arguments: ["position": "Software Engineer"]
         )
 
         #expect(description == "Interview preparation prompt")

Tests/MCPTests/ResourceTests.swift

@@ -13,15 +13,15 @@ struct ResourceTests {
             title: "Test Resource Title",
             description: "A test resource",
             mimeType: "text/plain",
-            metadata: ["key": "value"]
+            size: 1024
         )
 
         #expect(resource.name == "test_resource")
         #expect(resource.uri == "file://test.txt")
         #expect(resource.title == "Test Resource Title")
         #expect(resource.description == "A test resource")
         #expect(resource.mimeType == "text/plain")
-        #expect(resource.metadata?["key"] == "value")
+        #expect(resource.size == 1024)
     }
 
     @Test("Resource encoding and decoding")
@@ -32,7 +32,7 @@ struct ResourceTests {
             title: "Test Resource Title",
             description: "Test resource description",
             mimeType: "text/plain",
-            metadata: ["key1": "value1", "key2": "value2"]
+            size: 512
         )
 
         let encoder = JSONEncoder()
@@ -46,7 +46,7 @@ struct ResourceTests {
         #expect(decoded.title == resource.title)
         #expect(decoded.description == resource.description)
         #expect(decoded.mimeType == resource.mimeType)
-        #expect(decoded.metadata == resource.metadata)
+        #expect(decoded.size == resource.size)
     }
 
     @Test("Resource.Content text initialization and encoding")

Tests/MCPTests/RoundtripTests.swift

@@ -57,17 +57,17 @@ struct RoundtripTests {
         }
         await server.withMethodHandler(CallTool.self) { request in
             guard request.name == "add" else {
-                return CallTool.Result(content: [.text("Invalid tool name")], isError: true)
+                return CallTool.Result(content: [.text(text: "Invalid tool name", annotations: nil, _meta: nil)], isError: true)
             }
 
             guard let a = request.arguments?["a"]?.intValue,
                 let b = request.arguments?["b"]?.intValue
             else {
                 return CallTool.Result(
-                    content: [.text("Did not receive valid arguments")], isError: true)
+                    content: [.text(text: "Did not receive valid arguments", annotations: nil, _meta: nil)], isError: true)
             }
 
-            return CallTool.Result(content: [.text("\(a + b)")])
+            return CallTool.Result(content: [.text(text: "\(a + b)", annotations: nil, _meta: nil)])
         }
 
         // Add resource handlers to server
@@ -151,7 +151,7 @@ struct RoundtripTests {
         let callToolTask = Task {
             let result = try await client.callTool(name: "add", arguments: ["a": 1, "b": 2])
             #expect(result.isError == nil)
-            #expect(result.content == [.text("3")])
+            #expect(result.content == [.text(text: "3", annotations: nil, _meta: nil)])
         }
 
         try await withThrowingTaskGroup(of: Void.self) { group in