Merge pull request #50 from DeluxeAlonso/feature/current-page-index-c…

…hange

Adds currentPageIndexDidChange property for DLAutoSlidePageViewController

Sources/DLAutoSlidePageViewController.swift

@@ -24,7 +24,14 @@ open class DLAutoSlidePageViewController: UIPageViewController {
     private (set) public var pages: [UIViewController] = []
     private (set) public var configuration: AutoSlideConfiguration = DefaultAutoSlideConfiguration.shared
 
-    private var currentPageIndex: Int = 0
+    private var currentPageIndex: Int = 0 {
+        didSet {
+            currentPageIndexDidChange?(oldValue, currentPageIndex)
+        }
+    }
+    /// Closure that takes as parameter the previous current page index and the new current page index.
+    public var currentPageIndexDidChange: ((Int, Int) -> Void)?
+
     private var nextPageIndex: Int = 0
     private var timer: Timer?
 

Tests/DLAutoSlidePageViewControllerTests.swift

@@ -14,6 +14,11 @@ struct TestConfiguration: AutoSlideConfiguration {
     var hidePageControl: Bool {
         testHidesPageControl
     }
+
+    var testTimeInterval: TimeInterval = 1.0
+    var timeInterval: TimeInterval {
+        testTimeInterval
+    }
 }
 
 final class DLAutoSlidePageViewControllerTests: XCTestCase {
@@ -54,4 +59,25 @@ final class DLAutoSlidePageViewControllerTests: XCTestCase {
         XCTAssertEqual(presentationIndex, 0)
     }
 
+    func testCurrentPageIndexDidChange() {
+        // Arrange
+        var testConfiguration = TestConfiguration()
+        testConfiguration.testTimeInterval = 0.0
+        let firstViewController = UIViewController()
+        let secondViewController = UIViewController()
+        let pages = [firstViewController, secondViewController]
+        let pageViewController = DLAutoSlidePageViewController(pages: pages, configuration: testConfiguration)
+        let expectation = XCTestExpectation(description: "currentPageIndexDidChange closure should be called.")
+        // Act
+        pageViewController.currentPageIndexDidChange = { previousIndex, newIndex in
+            XCTAssertEqual(previousIndex, 0)
+            XCTAssertEqual(newIndex, 1)
+            expectation.fulfill()
+        }
+        pageViewController.pageViewController(pageViewController, willTransitionTo: [secondViewController])
+        pageViewController.pageViewController(pageViewController, didFinishAnimating: true, previousViewControllers: [], transitionCompleted: true)
+        // Assert
+        wait(for: [expectation], timeout: 1)
+    }
+
 }