[Compacted] Adding tests for compacted()

Author: LucianoPAlmeida

Tests/SwiftAlgorithmsTests/CompactedTests.swift

@@ -0,0 +1,53 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Algorithms open source project
+//
+// Copyright (c) 2020 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+//
+//===----------------------------------------------------------------------===//
+
+import XCTest
+import Algorithms
+
+final class CompactedTests: XCTestCase {
+
+  var tests: [[Int?]] = [
+    [],
+    [0],
+    [nil],
+    [0, nil],
+    [nil, 0],
+    [0, nil, 1, nil, 2, nil],
+    [0, 1, 2, nil, nil, nil],
+    [nil, nil, nil, 0, 1, 2],
+    [nil, nil, nil, nil, nil, nil]
+  ]
+  
+  func testCompactedSequence() {
+    for array in self.tests {
+      let seq = AnySequence(array)
+      XCTAssertEqualSequences(seq.compactMap({ $0 }), seq.compacted())
+    }
+  }
+  
+  func testCompactedCollection() {
+    for array in self.tests {
+      XCTAssertEqualSequences(array.compactMap({ $0 }), array.compacted())
+    }
+  }
+  
+  func testCompactedBidirectionalCollection() {
+    for array in self.tests {
+      XCTAssertEqualSequences(array.compactMap({ $0 }).reversed(), array.compacted().reversed())
+    }
+  }
+  
+  func testCollectionTraversals() {
+    for array in self.tests {
+      validateIndexTraversals(array)
+    }
+  }
+}