Added support for CollectionType and first Unit Test

Author: davecom

.gitignore

@@ -1,3 +1,6 @@
+.DS_Store
+.Trashes
+*.swp
 # Xcode
 #
 build/
@@ -24,10 +27,3 @@ DerivedData
 # http://guides.cocoapods.org/using/using-cocoapods.html#should-i-ignore-the-pods-directory-in-source-control
 #
 # Pods/
-
-# Carthage
-#
-# Add this line if you want to avoid checking in source code from Carthage dependencies.
-# Carthage/Checkouts
-
-Carthage/Build

SwiftPriorityQueue/SwiftPriorityQueue.swift

@@ -24,7 +24,12 @@
 
 // This code was inspired by Section 2.4 of Algorithms by Sedgewick & Wayne, 4th Edition
 
-class PriorityQueue<T: Comparable>: Printable, GeneratorType, SequenceType {
+/// A PriorityQueue takes objects to be pushed of any type that implements Comparable.
+/// It will pop the objects in the order that they would be sorted. A pop() or a push()
+/// can be accomplished in O(lg n) time. It can be specified whether the objects should
+/// be popped in ascending or descending order (Max Priority Queue or Min Priority Queue)
+/// at the time of initialization.
+class PriorityQueue<T: Comparable>: Printable, GeneratorType, SequenceType, CollectionType {
     private final var heap: [T] = []
     private let contrast: (T, T) -> Bool
 
@@ -118,7 +123,10 @@ class PriorityQueue<T: Comparable>: Printable, GeneratorType, SequenceType {
     //Implement GeneratorType
     typealias Element = T
     func next() -> Element? {
-        return pop()
+        if let e = pop() {
+            return e
+        }
+        return nil
     }
 
     //Implement SequenceType
@@ -127,4 +135,18 @@ class PriorityQueue<T: Comparable>: Printable, GeneratorType, SequenceType {
         return self
     }
 
+    //Implement CollectionType
+    typealias Index = Int
+    
+    var startIndex: Int {
+        return 0
+    }
+    
+    var endIndex: Int {
+        return count
+    }
+    
+    subscript(i: Int) -> T {
+        return heap[i]
+    }
 }

SwiftPriorityQueueTests/SwiftPriorityQueueTests.swift

@@ -33,4 +33,19 @@ class SwiftPriorityQueueTests: XCTestCase {
         }
     }
 
+    func testBasic() {
+        var pq: PriorityQueue<Int> = PriorityQueue<Int>()
+        for var i: Int = 0; i < 10; i++ {
+            pq.push(i);
+        }
+        
+        let expected: [Int] = [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
+        var actual: [Int] = []
+        for i in pq {
+            actual.append(i)
+        }
+        
+        XCTAssertEqual(expected, actual, "Basic 10 Integer Array Test Pass")
+    }
+    
 }