diff --git a/.travis.yml b/.travis.yml
index 633b870..d145f58 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,32 +9,29 @@ matrix:
       before_install:
         - wget -q -O - https://swift.org/keys/all-keys.asc | gpg --import -
         - cd ..
-        - export SWIFT_VERSION=swift-3.0.2-RELEASE
-        - wget https://swift.org/builds/swift-3.0.2-release/ubuntu1404/$SWIFT_VERSION/$SWIFT_VERSION-ubuntu14.04.tar.gz
+        - export SWIFT_VERSION=swift-3.1-RELEASE
+        - wget https://swift.org/builds/swift-3.1-release/ubuntu1404/$SWIFT_VERSION/$SWIFT_VERSION-ubuntu14.04.tar.gz
         - tar xzf $SWIFT_VERSION-ubuntu14.04.tar.gz
         - export PATH="${PWD}/${SWIFT_VERSION}-ubuntu14.04/usr/bin:${PATH}"
         - cd DBNetworkStack
       script:
         - swift test --verbose
     - os: osx
-      osx_image: xcode8.2
+      osx_image: xcode8.3
       language: objective-c
       env: "macOS"
       script:
         - set -o pipefail && xcodebuild -scheme DBNetworkStack -destination 'platform=OS X' test CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO -enableCodeCoverage NO | xcpretty
     - os: osx
-      osx_image: xcode8.2
+      osx_image: xcode8.3
       language: objective-c
       env: "iOS"
-      before_install:
-        - export SNAPSHOT_FORCE_DELETE=1
-        - fastlane snapshot reset_simulators
       script:
         - set -o pipefail && xcodebuild -scheme DBNetworkStack -destination 'platform=iOS Simulator,name=iPhone SE,OS=latest' test CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO -enableCodeCoverage YES | xcpretty
       after_success:
         - bash <(curl -s https://codecov.io/bash)
     - os: osx
-      osx_image: xcode8.2
+      osx_image: xcode8.3
       language: objective-c
       env: "watchOS"
       before_install:
@@ -43,17 +40,14 @@ matrix:
       script:
         - set -o pipefail && xcodebuild -scheme DBNetworkStack -destination 'platform=watchOS Simulator,name=Apple Watch - 38mm,OS=latest' build CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO | xcpretty
     - os: osx
-      osx_image: xcode8.2
+      osx_image: xcode8.3
       language: objective-c
       env: "tvOS"
-      before_install:
-        - export SNAPSHOT_FORCE_DELETE=1
-        - fastlane snapshot reset_simulators
       script:
         - set -o pipefail && xcodebuild -scheme DBNetworkStack -destination 'platform=tvOS Simulator,name=Apple TV 1080p,OS=latest' test CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO -enableCodeCoverage NO | xcpretty
     - os: osx
-      osx_image: xcode8.2
+      osx_image: xcode8.3
       language: objective-c
       env: "Swift Package Manager"
       script:
-        - swift build --clean && swift test
\ No newline at end of file
+        - swift build --clean && swift test
diff --git a/Source/DBNetworkStackError.swift b/Source/DBNetworkStackError.swift
index e38fab3..44a289b 100644
--- a/Source/DBNetworkStackError.swift
+++ b/Source/DBNetworkStackError.swift
@@ -89,7 +89,11 @@ extension DBNetworkStackError : CustomDebugStringConvertible {
         case .requestError(let error):
             return "Request error: \(error)"
         case .serverError(let response, let data):
-            return "Server error: \(response), response: ".appendingContentsOf(data: data)
+            if let response = response {
+                return "Server error: \(String(describing: response)), response: ".appendingContentsOf(data: data)
+            } else {
+                return "Server error: nil, response: ".appendingContentsOf(data: data)
+            }
         case .missingBaseURL:
             return "Missing base url error"
         }
diff --git a/Source/HTTPMethod.swift b/Source/HTTPMethod.swift
index 2e22cf0..2befe8e 100644
--- a/Source/HTTPMethod.swift
+++ b/Source/HTTPMethod.swift
@@ -26,6 +26,8 @@
 //
 
 import Foundation
+
+// swiftlint:disable identifier_name
 /**
  HTTP Methods
  
diff --git a/Source/ModifyRequestNetworkService.swift b/Source/ModifyRequestNetworkService.swift
index 83b7c03..0a8249e 100644
--- a/Source/ModifyRequestNetworkService.swift
+++ b/Source/ModifyRequestNetworkService.swift
@@ -27,6 +27,7 @@
 //
 
 import Foundation
+import Dispatch
 
 /// `ModifyRequestNetworkService` can be composed with a networkService to modify all outgoing requests.
 /// One could add auth tokens or API keys for specifics URLs.
diff --git a/Source/NetworkService.swift b/Source/NetworkService.swift
index c6146e6..c582dc1 100644
--- a/Source/NetworkService.swift
+++ b/Source/NetworkService.swift
@@ -26,6 +26,7 @@
 //
 
 import Foundation
+import Dispatch
 
 /**
  `NetworkService` handles network request for resources by using a given `NetworkAccessProviding`
diff --git a/Source/NetworkTaskMock.swift b/Source/NetworkTaskMock.swift
index 63080d9..86e6361 100644
--- a/Source/NetworkTaskMock.swift
+++ b/Source/NetworkTaskMock.swift
@@ -49,6 +49,6 @@ public class NetworkTaskMock: NetworkTaskRepresenting {
     }
     
     public var progress: Progress {
-        return Progress()
+        return Progress(totalUnitCount: 0)
     }
 }
diff --git a/Source/URLSessionNetworkAccess.swift b/Source/URLSessionNetworkAccess.swift
index 3924d0e..b6231ba 100644
--- a/Source/URLSessionNetworkAccess.swift
+++ b/Source/URLSessionNetworkAccess.swift
@@ -34,7 +34,12 @@ extension URLSession: URLSessionProtocol {}
 
 extension URLSessionDataTask: NetworkTaskRepresenting {
     public var progress: Progress {
-        let totalBytesExpected = response?.expectedContentLength ?? NSURLSessionTransferSizeUnknown
+        #if os(Linux)
+            let SessionTransferSizeUnknown = URLSessionTransferSizeUnknown
+        #else
+            let SessionTransferSizeUnknown = NSURLSessionTransferSizeUnknown
+        #endif
+        let totalBytesExpected = response?.expectedContentLength ?? SessionTransferSizeUnknown
         let progress = Progress(totalUnitCount: totalBytesExpected)
         progress.totalUnitCount = totalBytesExpected
         progress.completedUnitCount = countOfBytesReceived
diff --git a/Tests/DBNetworkStackTests/DBNetworkStackErrorTest.swift b/Tests/DBNetworkStackTests/DBNetworkStackErrorTest.swift
index 2c67859..4826794 100644
--- a/Tests/DBNetworkStackTests/DBNetworkStackErrorTest.swift
+++ b/Tests/DBNetworkStackTests/DBNetworkStackErrorTest.swift
@@ -140,7 +140,7 @@ class DBNetworkStackErrorTest: XCTestCase {
 
     func testUnknownError_unauthorized_description() {
         //Given
-        let response = HTTPURLResponse()
+        let response: HTTPURLResponse! = HTTPURLResponse(url: url, statusCode: 0, httpVersion: "1.1", headerFields: nil)
         let data = "dataString".data(using: .utf8)
         let error: DBNetworkStackError = .unauthorized(response: response, data: data)
         
@@ -149,12 +149,12 @@ class DBNetworkStackErrorTest: XCTestCase {
         
         //Then
         XCTAssert(debugDescription.hasPrefix("Authorization error: <NSHTTPURLResponse: "))
-        XCTAssert(debugDescription.hasSuffix("> { URL: (null) } { status code: 0, headers {\n} }, response: dataString"))
+        XCTAssert(debugDescription.hasSuffix("> { URL: https://bahn.de } { status code: 0, headers {\n} }, response: dataString"))
     }
     
     func testUnknownError_clientError_description() {
         //Given
-        let response = HTTPURLResponse()
+        let response: HTTPURLResponse! = HTTPURLResponse(url: url, statusCode: 0, httpVersion: "1.1", headerFields: nil)
         let data = "dataString".data(using: .utf8)
         let error: DBNetworkStackError = .clientError(response: response, data: data)
         
@@ -163,7 +163,7 @@ class DBNetworkStackErrorTest: XCTestCase {
         
         //Then
         XCTAssert(debugDescription.hasPrefix("Client error: <NSHTTPURLResponse: "))
-        XCTAssert(debugDescription.hasSuffix("> { URL: (null) } { status code: 0, headers {\n} }, response: dataString"))
+        XCTAssert(debugDescription.hasSuffix("> { URL: https://bahn.de } { status code: 0, headers {\n} }, response: dataString"))
     }
     
     func testUnknownError_serializationError_description() {
diff --git a/Tests/DBNetworkStackTests/JSONArrayResourceTest.swift b/Tests/DBNetworkStackTests/JSONArrayResourceTest.swift
index 3baa2d1..9cb4db7 100644
--- a/Tests/DBNetworkStackTests/JSONArrayResourceTest.swift
+++ b/Tests/DBNetworkStackTests/JSONArrayResourceTest.swift
@@ -50,7 +50,7 @@ class JSONArrayResourceTest: XCTestCase {
     func testResource_WithInvalidData() {
         //When
         do {
-            let _ = try resource.parse(Train.invalidJSONData)
+            _ = try resource.parse(Train.invalidJSONData)
             XCTFail()
         } catch {
             
@@ -60,7 +60,7 @@ class JSONArrayResourceTest: XCTestCase {
     func testResource_WithInvalidContainer() {
         //When
         do {
-            let _ = try resource.parse(Train.validJSONData)
+            _ = try resource.parse(Train.validJSONData)
             XCTFail()
         } catch {
         }
diff --git a/Tests/DBNetworkStackTests/NetworkRequestTest.swift b/Tests/DBNetworkStackTests/NetworkRequestTest.swift
index 0c6e90e..1bd0d57 100644
--- a/Tests/DBNetworkStackTests/NetworkRequestTest.swift
+++ b/Tests/DBNetworkStackTests/NetworkRequestTest.swift
@@ -54,7 +54,11 @@ class NetworkRequestTest: XCTestCase {
         //Then
         let urlRequest = request.urlRequest(with: baseURL)
         
-        XCTAssertEqual(urlRequest.url?.absoluteString, "https://www.bahn.de/index.html?test1=1&test2=2")
+        let reuqestURL: URL! = urlRequest.url
+        let query = URLComponents(url: reuqestURL, resolvingAgainstBaseURL: true)?.queryItems
+        XCTAssertEqual(query?.count, 2)
+        XCTAssert(query?.contains(where: { $0.name == "test1" && $0.value == "1" }) ?? false)
+        XCTAssert(query?.contains(where: { $0.name == "test2" && $0.value == "2" }) ?? false)
         XCTAssertEqual(urlRequest.httpMethod, httpMethod.rawValue)
         XCTAssertEqual(urlRequest.httpBody, body)
         XCTAssertEqual(urlRequest.allHTTPHeaderFields ?? [:], headerFields)
diff --git a/Tests/DBNetworkStackTests/RetryNetworkserviceTest.swift b/Tests/DBNetworkStackTests/RetryNetworkserviceTest.swift
index 5d1e02a..a001afd 100644
--- a/Tests/DBNetworkStackTests/RetryNetworkserviceTest.swift
+++ b/Tests/DBNetworkStackTests/RetryNetworkserviceTest.swift
@@ -91,7 +91,7 @@ class RetryNetworkserviceTest: XCTestCase {
     func testRetryRequest_shouldNotRetry() {
         //Given
         let shoudlRetry = false
-        var error: DBNetworkStackError?
+        var capturedError: DBNetworkStackError?
         
         //When
         weak var task: NetworkTaskRepresenting?
@@ -102,13 +102,13 @@ class RetryNetworkserviceTest: XCTestCase {
             block()
         }).request(resource, onCompletion: { _ in
             XCTFail()
-        }, onError: { err in
-           error = err
+        }, onError: { error in
+           capturedError = error
         })
         networkServiceMock.returnError(with: .unknownError, count: 3)
         
         //Then
         XCTAssertNil(task)
-        XCTAssertNotNil(error)
+        XCTAssertNotNil(capturedError)
     }
 }
diff --git a/Tests/DBNetworkStackTests/RetryTaskTest.swift b/Tests/DBNetworkStackTests/RetryTaskTest.swift
index 7ddd48d..598d2e6 100644
--- a/Tests/DBNetworkStackTests/RetryTaskTest.swift
+++ b/Tests/DBNetworkStackTests/RetryTaskTest.swift
@@ -51,9 +51,9 @@ class RetryTaskTest: XCTestCase {
         //Given
         var successValue: Int?
         var task: RetryNetworkTask<Int>? = RetryNetworkTask(maxmimumNumberOfRetries: 1, idleTimeInterval: 1,
-                                                            shouldRetry: { err in return true}, onSuccess: { (t: Int) in
-            successValue = t
-        }, onError: { err in
+                                                            shouldRetry: { _ in return true}, onSuccess: { (value: Int) in
+            successValue = value
+        }, onError: { _ in
         }, retryAction: {sucess, _ in
             sucess(0)
             return NetworkTaskMock()
@@ -112,12 +112,12 @@ class RetryTaskTest: XCTestCase {
         var task: RetryNetworkTask<Int>? = RetryNetworkTask(maxmimumNumberOfRetries: 3, idleTimeInterval: 0.3,
                                                             shouldRetry: { _ in return true}, onSuccess: { (_: Int) in
         }, onError: { _ in
-        }, retryAction: {a, b in
+        }, retryAction: { onSucess, onError in
             numerOfRertrys += 1
             if numerOfRertrys == 3 {
-                a(0)
+                onSucess(0)
             } else {
-                b(self.mockError)
+                onError(self.mockError)
             }
             
             return NetworkTaskMock()
@@ -139,12 +139,12 @@ class RetryTaskTest: XCTestCase {
     }
     
     func testShouldNotRetry() {
-        var error: DBNetworkStackError?
+        var capturedError: DBNetworkStackError?
         var task: RetryNetworkTask<Int>? = RetryNetworkTask(maxmimumNumberOfRetries: 3, idleTimeInterval: 0.3,
-                                                            shouldRetry: { err in return false}, onSuccess: { _ in
+                                                            shouldRetry: { _ in return false}, onSuccess: { _ in
             
-        }, onError: { err in
-            error = err
+        }, onError: { error in
+            capturedError = error
         }, retryAction: { _, _ in
             XCTFail()
             return NetworkTaskMock()
@@ -161,6 +161,6 @@ class RetryTaskTest: XCTestCase {
         onError = nil
         
         XCTAssertNil(weakTask)
-        XCTAssertNotNil(error)
+        XCTAssertNotNil(capturedError)
     }
 }
diff --git a/Tests/DBNetworkStackTests/URLSessionNetworkAccessTest.swift b/Tests/DBNetworkStackTests/URLSessionNetworkAccessTest.swift
index 7dda4db..3767357 100644
--- a/Tests/DBNetworkStackTests/URLSessionNetworkAccessTest.swift
+++ b/Tests/DBNetworkStackTests/URLSessionNetworkAccessTest.swift
@@ -57,7 +57,7 @@ class URLSessionNetworkAccessTest: XCTestCase {
     }
     
     func testURLSession_MatchesTypeOfNetworkAccess() {
-        let _: NetworkAccessProviding = URLSession(configuration: .default)
+        _ = URLSession(configuration: .default) as NetworkAccessProviding
     }
     
     func test_URLSessionCreatsDataTask() {