Add tests for uniquePermutations

Author: natecook1000

Tests/SwiftAlgorithmsTests/UniquePermutationsTests.swift

@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+@testable import Algorithms
+
+final class UniquePermutationsTests: XCTestCase {
+  static let numbers = [1, 1, 1, 2, 3]
+  
+  static let numbersPermutations: [[ArraySlice<Int>]] = [
+    // 0
+    [[]],
+    // 1
+    [[1], [2], [3]],
+    // 2
+    [[1, 1], [1, 2], [1, 3], [2, 1], [2, 3], [3, 1], [3, 2]],
+    // 3
+    [[1, 1, 1], [1, 1, 2], [1, 1, 3],
+     [1, 2, 1], [1, 2, 3], [1, 3, 1], [1, 3, 2],
+     [2, 1, 1], [2, 1, 3], [2, 3, 1],
+     [3, 1, 1], [3, 1, 2], [3, 2, 1]],
+    // 4
+    [[1, 1, 1, 2], [1, 1, 1, 3],
+     [1, 1, 2, 1], [1, 1, 2, 3],
+     [1, 1, 3, 1], [1, 1, 3, 2],
+     [1, 2, 1, 1], [1, 2, 1, 3], [1, 2, 3, 1],
+     [1, 3, 1, 1], [1, 3, 1, 2], [1, 3, 2, 1],
+     [2, 1, 1, 1], [2, 1, 1, 3], [2, 1, 3, 1], [2, 3, 1, 1],
+     [3, 1, 1, 1], [3, 1, 1, 2], [3, 1, 2, 1], [3, 2, 1, 1]],
+    // 5
+    [[1, 1, 1, 2, 3], [1, 1, 1, 3, 2],
+     [1, 1, 2, 1, 3], [1, 1, 2, 3, 1],
+     [1, 1, 3, 1, 2], [1, 1, 3, 2, 1],
+     [1, 2, 1, 1, 3], [1, 2, 1, 3, 1], [1, 2, 3, 1, 1],
+     [1, 3, 1, 1, 2], [1, 3, 1, 2, 1], [1, 3, 2, 1, 1],
+     [2, 1, 1, 1, 3], [2, 1, 1, 3, 1], [2, 1, 3, 1, 1], [2, 3, 1, 1, 1],
+     [3, 1, 1, 1, 2], [3, 1, 1, 2, 1], [3, 1, 2, 1, 1], [3, 2, 1, 1, 1]]
+  ]
+
+  func testEmpty() {
+    XCTAssertEqualSequences(([] as [Int]).uniquePermutations(), [[]])
+    XCTAssertEqualSequences(([] as [Int]).uniquePermutations(ofCount: 0), [[]])
+    XCTAssertEqualSequences(([] as [Int]).uniquePermutations(ofCount: 1), [])
+    XCTAssertEqualSequences(([] as [Int]).uniquePermutations(ofCount: 1...3), [])
+  }
+  
+  func testSingleCounts() {
+    for (k, expectation) in Self.numbersPermutations.enumerated() {
+      XCTAssertEqualSequences(expectation, Self.numbers.uniquePermutations(ofCount: k))
+    }
+  }
+  
+  func testRanges() {
+    for lower in Self.numbersPermutations.indices {
+      // upper bounded
+      XCTAssertEqualSequences(
+        Self.numbersPermutations[...lower].joined(),
+        Self.numbers.uniquePermutations(ofCount: ...lower))
+      
+      // lower bounded
+      XCTAssertEqualSequences(
+        Self.numbersPermutations[lower...].joined(),
+        Self.numbers.uniquePermutations(ofCount: lower...))
+
+      for upper in lower..<Self.numbersPermutations.count {
+        XCTAssertEqualSequences(
+          Self.numbersPermutations[lower..<upper].joined(),
+          Self.numbers.uniquePermutations(ofCount: lower..<upper))
+      }
+    }
+  }
+}