[test] Test reachability usage for online requests

NOTE: This requires to mock `NetworkReachability` during the tests.

Author: Clément Le Provost

AlgoliaSearch.xcodeproj/project.pbxproj

@@ -148,6 +148,10 @@
 		BCDA73791CA546800082B197 /* NetworkTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = BCDA73771CA546800082B197 /* NetworkTests.swift */; };
 		BCDA737E1CA555070082B197 /* MockURLSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = BCDA737D1CA555070082B197 /* MockURLSession.swift */; };
 		BCDA737F1CA555070082B197 /* MockURLSession.swift in Sources */ = {isa = PBXBuildFile; fileRef = BCDA737D1CA555070082B197 /* MockURLSession.swift */; };
+		BCE2E9851E23949D00F189F3 /* MockNetworkReachability.swift in Sources */ = {isa = PBXBuildFile; fileRef = BCE2E9841E23949D00F189F3 /* MockNetworkReachability.swift */; };
+		BCE2E9861E23949D00F189F3 /* MockNetworkReachability.swift in Sources */ = {isa = PBXBuildFile; fileRef = BCE2E9841E23949D00F189F3 /* MockNetworkReachability.swift */; };
+		BCE2E9871E23949D00F189F3 /* MockNetworkReachability.swift in Sources */ = {isa = PBXBuildFile; fileRef = BCE2E9841E23949D00F189F3 /* MockNetworkReachability.swift */; };
+		BCE2E9881E23949D00F189F3 /* MockNetworkReachability.swift in Sources */ = {isa = PBXBuildFile; fileRef = BCE2E9841E23949D00F189F3 /* MockNetworkReachability.swift */; };
 		BCEE36811E0830810091D113 /* settings.json in Resources */ = {isa = PBXBuildFile; fileRef = BCEE36801E0830810091D113 /* settings.json */; };
 		BCEE36831E08309F0091D113 /* objects.json in Resources */ = {isa = PBXBuildFile; fileRef = BCEE36821E08309F0091D113 /* objects.json */; };
 		BCFC281C1D92660C00BFE0A0 /* MirroredIndexTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = BCFC281B1D92660C00BFE0A0 /* MirroredIndexTests.swift */; };
@@ -242,6 +246,7 @@
 		BCD57D3B1D89B1EA00C5DE68 /* OfflineTestCase.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OfflineTestCase.swift; sourceTree = "<group>"; };
 		BCDA73771CA546800082B197 /* NetworkTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = NetworkTests.swift; sourceTree = "<group>"; };
 		BCDA737D1CA555070082B197 /* MockURLSession.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MockURLSession.swift; sourceTree = "<group>"; };
+		BCE2E9841E23949D00F189F3 /* MockNetworkReachability.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MockNetworkReachability.swift; sourceTree = "<group>"; };
 		BCEE36801E0830810091D113 /* settings.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = settings.json; sourceTree = "<group>"; };
 		BCEE36821E08309F0091D113 /* objects.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = objects.json; sourceTree = "<group>"; };
 		BCFC281B1D92660C00BFE0A0 /* MirroredIndexTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MirroredIndexTests.swift; sourceTree = "<group>"; };
@@ -399,6 +404,7 @@
 				5D8FFA371AAB08830078869E /* ClientTests.swift */,
 				5D44D0261B362648008369AC /* Helpers.swift */,
 				5D8FFA391AAB0AB80078869E /* IndexTests.swift */,
+				BCE2E9841E23949D00F189F3 /* MockNetworkReachability.swift */,
 				BCDA737D1CA555070082B197 /* MockURLSession.swift */,
 				BCDA73771CA546800082B197 /* NetworkTests.swift */,
 				BC72244C1D9C137B00B56908 /* OnlineTestCase.swift */,
@@ -920,6 +926,7 @@
 				BCDA737E1CA555070082B197 /* MockURLSession.swift in Sources */,
 				BC4DDF131DD13423004D9A6E /* PlacesQueryTests.swift in Sources */,
 				BC4A7F3C1CB5373E00AF1DCB /* CancelTests.swift in Sources */,
+				BCE2E9851E23949D00F189F3 /* MockNetworkReachability.swift in Sources */,
 				5D44D0271B362648008369AC /* Helpers.swift in Sources */,
 				5D8FFA3A1AAB0AB80078869E /* IndexTests.swift in Sources */,
 				BC85EA701D82C8C3009E9E7D /* ObjectiveCBridging.m in Sources */,
@@ -964,6 +971,7 @@
 				BCDA737F1CA555070082B197 /* MockURLSession.swift in Sources */,
 				BC4DDF141DD13423004D9A6E /* PlacesQueryTests.swift in Sources */,
 				BC4A7F3D1CB5373E00AF1DCB /* CancelTests.swift in Sources */,
+				BCE2E9861E23949D00F189F3 /* MockNetworkReachability.swift in Sources */,
 				5D44D0281B362648008369AC /* Helpers.swift in Sources */,
 				5DB2515D1AAD9F3B00945339 /* IndexTests.swift in Sources */,
 				BC582C5D1D82B453007B815A /* ObjectiveCBridging.m in Sources */,
@@ -1063,6 +1071,7 @@
 				BCD1F5741CC61DB80006E227 /* QueryTests.swift in Sources */,
 				BC4DDF151DD13423004D9A6E /* PlacesQueryTests.swift in Sources */,
 				BCD1F5711CC61DB80006E227 /* IndexTests.swift in Sources */,
+				BCE2E9871E23949D00F189F3 /* MockNetworkReachability.swift in Sources */,
 				BCD1F56E1CC61DB80006E227 /* CancelTests.swift in Sources */,
 				BCD1F5701CC61DB80006E227 /* Helpers.swift in Sources */,
 				BC85EA711D82C8C4009E9E7D /* ObjectiveCBridging.m in Sources */,
@@ -1076,6 +1085,7 @@
 			files = (
 				BCD57D3D1D89B1EA00C5DE68 /* OfflineIndexTests.swift in Sources */,
 				BCFC281D1D92670100BFE0A0 /* Helpers.swift in Sources */,
+				BCE2E9881E23949D00F189F3 /* MockNetworkReachability.swift in Sources */,
 				BCD57D3E1D89B1EA00C5DE68 /* OfflineTestCase.swift in Sources */,
 				BCFC281C1D92660C00BFE0A0 /* MirroredIndexTests.swift in Sources */,
 				BCD57D3C1D89B1EA00C5DE68 /* OfflineClientTests.swift in Sources */,

Source/AbstractClient.swift

@@ -187,8 +187,9 @@ internal struct HostStatus {
 
     #if !os(watchOS)
 
-    /// Network reachability tester.
-    internal let reachability = NetworkReachability()
+    /// Network reachability detecter.
+    internal var reachability: NetworkReachability = SystemNetworkReachability()
+    // ^ NOTE: Not constant only for the sake of mocking during unit tests.
 
     /// Whether to use network reachability to decide if online requests should be attempted.
     ///

Source/NetworkReachability.swift

@@ -27,9 +27,21 @@ import Foundation
 import SystemConfiguration
 
 
-/// Tests network reachability.
+/// Detects network reachability.
 ///
-class NetworkReachability {
+protocol NetworkReachability {
+    // MARK: Properties
+    
+    /// Test if network connectivity is currently available.
+    ///
+    /// - returns: true if network connectivity is available, false otherwise.
+    ///
+    func isReachable() -> Bool
+}
+    
+/// Detects network reachability using the system's built-in mechanism.
+///
+class SystemNetworkReachability: NetworkReachability {
     // MARK: Properties
 
     /// Reachability handle used to test connectivity.
@@ -39,7 +51,7 @@ class NetworkReachability {
 
     init() {
         // Create reachability handle to an all-zeroes address.
-        var zeroAddress = NetworkReachability.zeroAddress
+        var zeroAddress = SystemNetworkReachability.zeroAddress
         reachability = withUnsafePointer(to: &zeroAddress) {
             $0.withMemoryRebound(to: sockaddr.self, capacity: 1) {
                 SCNetworkReachabilityCreateWithAddress(nil, $0)

Tests/ClientTests.swift

@@ -456,4 +456,35 @@ class ClientTests: OnlineTestCase {
         })
         self.waitForExpectations(timeout: expectationTimeout, handler: nil)
     }
+
+    /// Test that we take reachability into account when making requests, unless `useReachability` is set to false.
+    ///
+    func testUseReachability() {
+        let expectation = self.expectation(description: #function)
+
+        // Pretend that we are offline.
+        let reachability = MockNetworkReachability()
+        client.reachability = reachability
+        reachability.reachable = false
+        
+        // Check that requests fail right away.
+        let startTime = Date()
+        client.listIndexes { (content, error) in
+            let stopTime = Date()
+            let duration = stopTime.timeIntervalSince(startTime)
+            guard let error = error as? NSError else { XCTFail("Request should have failed"); expectation.fulfill(); return }
+            XCTAssertEqual(NSURLErrorDomain, error.domain)
+            XCTAssertEqual(NSURLErrorNotConnectedToInternet, error.code)
+            XCTAssert(duration < min(self.client.searchTimeout, self.client.timeout)) // check that we failed without waiting for the timeout
+
+            // Choose to ignore reachability now, and check that requests are performed, although network is supposedly down.
+            self.client.useReachability = false
+            self.client.listIndexes { (content, error) in
+                // The request should work, since we are actually connected (fake reachability)!
+                XCTAssertNil(error)
+                expectation.fulfill()
+            }
+        }
+        self.waitForExpectations(timeout: expectationTimeout, handler: nil)
+    }
 }

Tests/MockNetworkReachability.swift

@@ -0,0 +1,36 @@
+//
+//  Copyright (c) 2016 Algolia
+//  http://www.algolia.com/
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+//
+
+@testable import AlgoliaSearch
+import Foundation
+
+
+/// A simple mock of `NetworkReachability` that just returns a stored state.
+///
+public class MockNetworkReachability: AlgoliaSearch.NetworkReachability {
+    public var reachable: Bool = true
+    
+    public func isReachable() -> Bool {
+        return reachable
+    }
+}