Implement XCTAssertIdentical & XCTAssertNotIdentical

These functions are available in Xcode 12.5, but aren't available on Linux/Windows. This change adds the implementations for them.

Author: egorzhdan

Sources/XCTest/Public/XCTAssert.swift

@@ -13,6 +13,8 @@
 private enum _XCTAssertion {
     case equal
     case equalWithAccuracy
+    case identical
+    case notIdentical
     case greaterThan
     case greaterThanOrEqual
     case lessThan
@@ -32,6 +34,8 @@ private enum _XCTAssertion {
         switch(self) {
         case .equal: return "XCTAssertEqual"
         case .equalWithAccuracy: return "XCTAssertEqual"
+        case .identical: return "XCTAssertIdentical"
+        case .notIdentical: return "XCTAssertNotIdentical"
         case .greaterThan: return "XCTAssertGreaterThan"
         case .greaterThanOrEqual: return "XCTAssertGreaterThanOrEqual"
         case .lessThan: return "XCTAssertLessThan"
@@ -206,6 +210,34 @@ public func XCTAssertEqualWithAccuracy<T: FloatingPoint>(_ expression1: @autoclo
     XCTAssertEqual(try expression1(), try expression2(), accuracy: accuracy, message(), file: file, line: line)
 }
 
+private func describe(_ object: AnyObject?) -> String {
+    return object == nil ? String(describing: object) : String(describing: object!)
+}
+
+/// Asserts that two values are identical.
+public func XCTAssertIdentical(_ expression1: @autoclosure () throws -> AnyObject?, _ expression2: @autoclosure () throws -> AnyObject?, _ message: @autoclosure () -> String = "", file: StaticString = #filePath, line: UInt = #line) {
+    _XCTEvaluateAssertion(.identical, message: message(), file: file, line: line) {
+        let (value1, value2) = (try expression1(), try expression2())
+        if value1 === value2 {
+            return .success
+        } else {
+            return .expectedFailure("(\"\(describe(value1))\") is not identical to (\"\(describe(value2))\")")
+        }
+    }
+}
+
+/// Asserts that two values aren't identical.
+public func XCTAssertNotIdentical(_ expression1: @autoclosure () throws -> AnyObject?, _ expression2: @autoclosure () throws -> AnyObject?, _ message: @autoclosure () -> String = "", file: StaticString = #filePath, line: UInt = #line) {
+    _XCTEvaluateAssertion(.notIdentical, message: message(), file: file, line: line) {
+        let (value1, value2) = (try expression1(), try expression2())
+        if value1 !== value2 {
+            return .success
+        } else {
+            return .expectedFailure("(\"\(describe(value1))\") is identical to (\"\(describe(value2))\")")
+        }
+    }
+}
+
 public func XCTAssertFalse(_ expression: @autoclosure () throws -> Bool, _ message: @autoclosure () -> String = "", file: StaticString = #file, line: UInt = #line) {
     _XCTEvaluateAssertion(.`false`, message: message(), file: file, line: line) {
         let value = try expression()

Tests/Functional/FailureMessagesTestCase/main.swift

@@ -28,6 +28,8 @@ class FailureMessagesTestCase: XCTestCase {
             ("testAssertFalse", testAssertFalse),
             ("testAssertGreaterThan", testAssertGreaterThan),
             ("testAssertGreaterThanOrEqual", testAssertGreaterThanOrEqual),
+            ("testAssertIdentical", testAssertIdentical),
+            ("testAssertNotIdentical", testAssertNotIdentical),
             ("testAssertLessThan", testAssertLessThan),
             ("testAssertLessThanOrEqual", testAssertLessThanOrEqual),
             ("testAssertNil", testAssertNil),
@@ -121,6 +123,27 @@ class FailureMessagesTestCase: XCTestCase {
         XCTAssertGreaterThanOrEqual(-1, 0, "message", file: "test.swift")
     }
 
+// CHECK: Test Case 'FailureMessagesTestCase.testAssertIdentical' started at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
+// CHECK: test.swift:[[@LINE+7]]: error: FailureMessagesTestCase.testAssertIdentical : XCTAssertIdentical failed: \("a"\) is not identical to \("b"\) - message
+// CHECK: Test Case 'FailureMessagesTestCase.testAssertIdentical' failed \(\d+\.\d+ seconds\)
+    func testAssertIdentical() {
+        let object = XCTestExpectation()
+        XCTAssertIdentical(object, object)
+        XCTAssertIdentical(nil, nil)
+        XCTAssertIdentical(true as AnyObject, true as AnyObject)
+        XCTAssertIdentical("a" as AnyObject, "b" as AnyObject, "message", file: "test.swift")
+    }
+
+// CHECK: Test Case 'FailureMessagesTestCase.testAssertNotIdentical' started at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
+// CHECK: test.swift:[[@LINE+6]]: error: FailureMessagesTestCase.testAssertNotIdentical : XCTAssertNotIdentical failed: \("nil"\) is identical to \("nil"\) - message
+// CHECK: Test Case 'FailureMessagesTestCase.testAssertNotIdentical' failed \(\d+\.\d+ seconds\)
+    func testAssertNotIdentical() {
+        XCTAssertNotIdentical("a" as AnyObject, "b" as AnyObject)
+        XCTAssertNotIdentical(true as AnyObject, false as AnyObject)
+        XCTAssertNotIdentical(XCTestExpectation(), XCTestExpectation())
+        XCTAssertNotIdentical(nil, nil, "message", file: "test.swift")
+    }
+
 // CHECK: Test Case 'FailureMessagesTestCase.testAssertLessThan' started at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
 // CHECK: test.swift:[[@LINE+3]]: error: FailureMessagesTestCase.testAssertLessThan : XCTAssertLessThan failed: \("0"\) is not less than \("0"\) - message
 // CHECK: Test Case 'FailureMessagesTestCase.testAssertLessThan' failed \(\d+\.\d+ seconds\)
@@ -213,11 +236,11 @@ class FailureMessagesTestCase: XCTestCase {
     }
 }
 // CHECK: Test Suite 'FailureMessagesTestCase' failed at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
-// CHECK: \t Executed 24 tests, with 24 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
+// CHECK: \t Executed 26 tests, with 26 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
 
 XCTMain([testCase(FailureMessagesTestCase.allTests)])
 
 // CHECK: Test Suite '.*\.xctest' failed at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
-// CHECK: \t Executed 24 tests, with 24 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
+// CHECK: \t Executed 26 tests, with 26 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
 // CHECK: Test Suite 'All tests' failed at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
-// CHECK: \t Executed 24 tests, with 24 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
+// CHECK: \t Executed 26 tests, with 26 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds