From 46460779e6a7df574347703926d262a8af73cb9b Mon Sep 17 00:00:00 2001
From: Bobby Bobak <bobak.art@gmail.com>
Date: Tue, 7 Apr 2020 10:11:42 +0100
Subject: [PATCH] Add tests for newly added methods and update the
 implementation of the CollectionViewDiffableDataSource with
 canMove/moveItemAt methods

---
 .../CollectionViewDiffableDataSource.swift    | 23 ++++++++++++
 ...ollectionViewDiffableDataSourceTests.swift | 18 ++++++++++
 Tests/TableViewDiffableDataSourceTests.swift  | 36 +++++++++++++++++++
 3 files changed, 77 insertions(+)

diff --git a/Sources/UIKit/CollectionViewDiffableDataSource.swift b/Sources/UIKit/CollectionViewDiffableDataSource.swift
index 789aedf..8c13d99 100644
--- a/Sources/UIKit/CollectionViewDiffableDataSource.swift
+++ b/Sources/UIKit/CollectionViewDiffableDataSource.swift
@@ -132,6 +132,29 @@ open class CollectionViewDiffableDataSource<SectionIdentifierType: Hashable, Ite
 
         return view
     }
+
+    /// Returns whether it is possible to edit a row at given index path.
+    ///
+    /// - Parameters:
+    ///   - collectionView: A collection view instance managed by `self`.
+    ///   - section: An index of section.
+    ///
+    /// - Returns: A boolean for row at specified index path.
+    open func collectionView(_ collectionView: UICollectionView, canMoveItemAt indexPath: IndexPath) -> Bool {
+        return false
+    }
+
+    /// Moves a row at given index path.
+    ///
+    /// - Parameters:
+    ///   - collectionView: A collection view instance managed by `self`.
+    ///   - sourceIndexPath: An index path for given cell position.
+    ///   - destinationIndexPath: An index path for target cell position.
+    ///
+    /// - Returns: Void.
+    public func collectionView(_ collectionView: UICollectionView, moveItemAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
+        // Empty implementation.
+    }
 }
 
 #endif
diff --git a/Tests/CollectionViewDiffableDataSourceTests.swift b/Tests/CollectionViewDiffableDataSourceTests.swift
index 872683a..212eff5 100644
--- a/Tests/CollectionViewDiffableDataSourceTests.swift
+++ b/Tests/CollectionViewDiffableDataSourceTests.swift
@@ -167,6 +167,24 @@ final class CollectionViewDiffableDataSourceTests: XCTestCase {
             cell
         )
     }
+
+    func testCanMoveRowAt() {
+        let collectionView = MockCollectionView()
+        let cell = UICollectionViewCell()
+        let dataSource = CollectionViewDiffableDataSource<Int, Int>(collectionView: collectionView) { _, _, _ in
+            cell
+        }
+
+        var snapshot = DiffableDataSourceSnapshot<Int, Int>()
+        snapshot.appendSections([0, 1, 2])
+        snapshot.appendItems([0, 1, 2], toSection: 0)
+        dataSource.apply(snapshot)
+
+        XCTAssertEqual(
+            dataSource.collectionView(collectionView, canMoveItemAt: IndexPath(item: 1, section: 0)),
+            false
+        )
+    }
 }
 
 final class MockCollectionView: UICollectionView {
diff --git a/Tests/TableViewDiffableDataSourceTests.swift b/Tests/TableViewDiffableDataSourceTests.swift
index ce3e1cb..8cec845 100644
--- a/Tests/TableViewDiffableDataSourceTests.swift
+++ b/Tests/TableViewDiffableDataSourceTests.swift
@@ -167,6 +167,42 @@ final class TableViewDiffableDataSourceTests: XCTestCase {
             cell
         )
     }
+
+    func testCanEditRowAt() {
+        let tableView = MockTableView()
+        let cell = UITableViewCell()
+        let dataSource = TableViewDiffableDataSource<Int, Int>(tableView: tableView) { _, _, _ in
+            cell
+        }
+
+        var snapshot = DiffableDataSourceSnapshot<Int, Int>()
+        snapshot.appendSections([0, 1, 2])
+        snapshot.appendItems([0, 1, 2], toSection: 0)
+        dataSource.apply(snapshot)
+
+        XCTAssertEqual(
+            dataSource.tableView(tableView, canEditRowAt: IndexPath(item: 1, section: 0)),
+            false
+        )
+    }
+
+    func testCanMoveRowAt() {
+        let tableView = MockTableView()
+        let cell = UITableViewCell()
+        let dataSource = TableViewDiffableDataSource<Int, Int>(tableView: tableView) { _, _, _ in
+            cell
+        }
+
+        var snapshot = DiffableDataSourceSnapshot<Int, Int>()
+        snapshot.appendSections([0, 1, 2])
+        snapshot.appendItems([0, 1, 2], toSection: 0)
+        dataSource.apply(snapshot)
+
+        XCTAssertEqual(
+            dataSource.tableView(tableView, canMoveRowAt: IndexPath(item: 1, section: 0)),
+            false
+        )
+    }
 }
 
 final class MockTableView: UITableView {