Add unit tests for NSArray mapping

Riot/SupportingFiles/Riot-Bridging-Header.h

@@ -43,3 +43,4 @@
 #import "RoomViewController.h"
 #import "ContactDetailsViewController.h"
 #import "GroupDetailsViewController.h"
+#import "NSArray+Element.h"

RiotTests/NSArray+Element.swift

@@ -0,0 +1,95 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import XCTest
+
+class NSArray_Element: XCTestCase {
+    
+    var array: NSArray = NSArray()  //  will contain strings
+
+    override func setUpWithError() throws {
+        // Put setup code here. This method is called before the invocation of each test method in the class.
+        array = NSArray(array: ["str 1", "string 2", "test string 3"])
+    }
+
+    override func tearDownWithError() throws {
+        // Put teardown code here. This method is called after the invocation of each test method in the class.
+    }
+
+    func testMap() throws {
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct results.
+        let mapped = array.vc_map { obj in
+            guard let string = obj as? String else {
+                XCTFail("Failed to setup test conditions")
+                return -1
+            }
+            return string.count
+        }
+        
+        XCTAssertEqual(array.count, mapped.count, "Every element in the array must be mapped")
+        XCTAssertTrue(mapped.allSatisfy({ $0 is Int }), "Every element must be an Int")
+        XCTAssertTrue(mapped.allSatisfy({ ($0 as? Int ?? 0) > 0 }), "Every element must be an Int, greater than zero")
+    }
+    
+    func testCompactMap() throws {
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct results.
+        let nilMapped: [Any] = array.vc_compactMap { obj in
+            return nil
+        }
+        XCTAssertTrue(nilMapped.isEmpty, "Mapped array must be empty")
+        
+        let onlyOneNilMapped: [Any] = array.vc_compactMap { obj in
+            guard let string = obj as? String else {
+                XCTFail("Failed to setup test conditions")
+                return -1
+            }
+            if string.hasSuffix("2") {
+                return nil
+            }
+            return string.count
+        }
+        
+        XCTAssertEqual(array.count - 1, onlyOneNilMapped.count, "Every element in the array must be mapped, except 'string 2'")
+        XCTAssertTrue(onlyOneNilMapped.allSatisfy({ $0 is Int }), "Every element must be an Int")
+        XCTAssertTrue(onlyOneNilMapped.allSatisfy({ ($0 as? Int ?? 0) > 0 }), "Every element must be an Int, greater than zero")
+    }
+    
+    func testFlatMap() throws {
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct results.
+        let emptyMapped: [Any] = array.vc_flatMap { obj in
+            return []
+        }
+        XCTAssertTrue(emptyMapped.isEmpty, "Mapped array must be empty")
+        
+        let twiceMapped: [Any] = array.vc_flatMap { obj in
+            guard let string = obj as? String else {
+                XCTFail("Failed to setup test conditions")
+                return []
+            }
+            return [string.count, string.count * 2]
+        }
+        XCTAssertEqual(array.count * 2, twiceMapped.count, "Mapped array must have twice time elements than the 'array'")
+        
+        let constantMapped: [Any] = array.vc_flatMap { obj in
+            return [1, 2]
+        }
+        XCTAssertEqual(array.count * 2, constantMapped.count, "Constantly mapped array must still have twice time elements than the 'array'")
+    }
+
+}