Merge pull request #23 from wokalski/bugfix/#22-identical-arrays

Fixes non-empty diff for identical single item arrays

Author: wokalski

Diff for: DiffTests/DiffTests.swift

@@ -86,6 +86,11 @@ class DiffTests: XCTestCase {
         }
     }
 
+    func testSingleElementArray() {
+        let changes = "a".diff(to: "a")
+        XCTAssertEqual(changes.elements.count, 0)
+    }
+
     func duplicateTraces(from: String, to: String) -> Bool {
         let traces = from.characters.diffTraces(to: to.characters)
         let tracesSet = Set(traces)

Diff for: Sources/Diff.swift

@@ -294,13 +294,15 @@ public extension Collection where Iterator.Element: Equatable {
         var item = traces.last!
         array.append(item)
 
-        for trace in traces.reversed() {
-            if trace.to.x == item.from.x && trace.to.y == item.from.y {
-                array.insert(trace, at: 0)
-                item = trace
-
-                if trace.from == Point(x: 0, y: 0) {
-                    break
+        if item.from != Point(x: 0, y: 0) {
+            for trace in traces.reversed() {
+                if trace.to.x == item.from.x && trace.to.y == item.from.y {
+                    array.insert(trace, at: 0)
+                    item = trace
+
+                    if trace.from == Point(x: 0, y: 0) {
+                        break
+                    }
                 }
             }
         }