Confirm RuntimeErrors to HTTPResponseConvertible

Sources/OpenAPIRuntime/Errors/RuntimeError.swift

@@ -13,7 +13,7 @@
 //===----------------------------------------------------------------------===//
 import protocol Foundation.LocalizedError
 import struct Foundation.Data
-
+import HTTPTypes
 /// Error thrown by generated code.
 internal enum RuntimeError: Error, CustomStringConvertible, LocalizedError, PrettyStringConvertible {
 
@@ -141,3 +141,43 @@ internal enum RuntimeError: Error, CustomStringConvertible, LocalizedError, Pret
 @_spi(Generated) public func throwUnexpectedResponseBody(expectedContent: String, body: any Sendable) throws -> Never {
     throw RuntimeError.unexpectedResponseBody(expectedContent: expectedContent, body: body)
 }
+
+/// HTTP Response status definition for ``RuntimeError``. 
+extension RuntimeError: HTTPResponseConvertible {
+    public var httpStatus: HTTPTypes.HTTPResponse.Status {
+        switch self {
+        case .invalidServerURL,
+                .invalidServerVariableValue:
+            .notFound
+        case .invalidExpectedContentType,
+                .missingCoderForCustomContentType,
+                .unexpectedContentTypeHeader:
+            .unsupportedMediaType
+        case .unexpectedAcceptHeader(_):
+            .notAcceptable
+        case .missingOrMalformedContentDispositionName:
+            .unprocessableContent
+        case .failedToDecodeStringConvertibleValue,
+                .invalidAcceptSubstring,
+                .invalidBase64String,
+                .invalidHeaderFieldName,
+                .malformedAcceptHeader,
+                .missingMultipartBoundaryContentTypeParameter,
+                .missingRequiredHeaderField,
+                .missingRequiredMultipartFormDataContentType,
+                .missingRequiredQueryParameter,
+                .missingRequiredPathParameter,
+                .missingRequiredRequestBody,
+                .pathUnset,
+                .unsupportedParameterStyle:
+            .badRequest
+        case .handlerFailed,
+                .middlewareFailed,
+                .missingRequiredResponseBody,
+                .transportFailed,
+                .unexpectedResponseStatus,
+                .unexpectedResponseBody:
+            .internalServerError
+        }
+    }
+}

Tests/OpenAPIRuntimeTests/Errors/Test_RuntimeError.swift

@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftOpenAPIGenerator open source project
+//
+// Copyright (c) 2024 Apple Inc. and the SwiftOpenAPIGenerator project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftOpenAPIGenerator project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import HTTPTypes
+@_spi(Generated) @testable import OpenAPIRuntime
+import XCTest
+
+struct MockRuntimeErrorHandler: Sendable {
+    var failWithError: (any Error)? = nil
+    func greet(_ input: String) async throws -> String {
+        if failWithError != nil { throw failWithError! }
+        guard input == "hello" else { throw TestError() }
+        return "bye"
+    }
+
+    static let requestBody: HTTPBody = HTTPBody("hello")
+    static let responseBody: HTTPBody = HTTPBody("bye")
+}
+
+final class Test_RuntimeError: XCTestCase {
+
+    func testRuntimeError_withUnderlyingErrorNotConfirming_returns500() async throws {
+
+        let server = UniversalServer(handler: MockRuntimeErrorHandler(failWithError: RuntimeError.transportFailed(TestError())),
+                                     middlewares: [ErrorHandlingMiddleware()])
+        let response = try await server.handle(
+            request: .init(soar_path: "/", method: .post),
+            requestBody: MockHandler.requestBody,
+            metadata: .init(),
+            forOperation: "op",
+            using: { MockRuntimeErrorHandler.greet($0) },
+            deserializer: { request, body, metadata in
+                let body = try XCTUnwrap(body)
+                return try await String(collecting: body, upTo: 10)
+            },
+            serializer: { output, _ in fatalError() }
+        )
+        XCTAssertEqual(response.0.status, .internalServerError)
+    }
+
+    func testRuntimeError_withUnderlyingErrorConfirming_returns500() async throws {
+
+        let server = UniversalServer(handler: MockRuntimeErrorHandler(failWithError: TestErrorConvertible.testError("Test Error")),
+                                     middlewares: [ErrorHandlingMiddleware()])
+        let response = try await server.handle(
+            request: .init(soar_path: "/", method: .post),
+            requestBody: MockHandler.requestBody,
+            metadata: .init(),
+            forOperation: "op",
+            using: { MockRuntimeErrorHandler.greet($0) },
+            deserializer: { request, body, metadata in
+                let body = try XCTUnwrap(body)
+                return try await String(collecting: body, upTo: 10)
+            },
+            serializer: { output, _ in fatalError() }
+        )
+        XCTAssertEqual(response.0.status, .badGateway)
+    }
+}
+
+enum TestErrorConvertible: Error, HTTPResponseConvertible {
+    case testError(String)
+
+    public var httpStatus: HTTPTypes.HTTPResponse.Status {
+        .badGateway
+    }
+}
+
+