Linux support (#116)

* Linux build

* Remove "result of call to 'registerClass' is unused" warning

Author: vox-humana

Sources/Mock.swift

@@ -10,6 +10,9 @@
 
 import Foundation
 import XCTest
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
 
 /// A Mock which can be used for mocking data requests with the `Mocker` by calling `Mocker.register(...)`.
 public struct Mock: Equatable {

Sources/Mocker.swift

@@ -7,6 +7,9 @@
 //
 
 import Foundation
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
 
 /// Can be used for registering Mocked data, returned by the `MockingURLProtocol`.
 public struct Mocker {
@@ -73,7 +76,7 @@ public struct Mocker {
 
     private init() {
         // Whenever someone is requesting the Mocker, we want the URL protocol to be activated.
-        URLProtocol.registerClass(MockingURLProtocol.self)
+        _ = URLProtocol.registerClass(MockingURLProtocol.self)
     }
 
     /// Register new Mocked data. If a mock for the same URL and HTTPMethod exists, it will be overwritten.

Sources/MockingURLProtocol.swift

@@ -7,6 +7,9 @@
 //
 
 import Foundation
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
 
 /// The protocol which can be used to send Mocked data back. Use the `Mocker` to register `Mock` data
 open class MockingURLProtocol: URLProtocol {