Merge pull request #1404 from spevans/pr_nsarray_paths_matching_extensions

Author: swift-ci

Foundation/NSArray.swift

@@ -653,7 +653,26 @@ open class NSArray : NSObject, NSCopying, NSMutableCopying, NSSecureCoding, NSCo
     }
 
     open func pathsMatchingExtensions(_ filterTypes: [String]) -> [String] {
-        NSUnimplemented()
+        guard filterTypes.count > 0 else {
+            return []
+        }
+
+        let extensions: [String] = filterTypes.map {
+            var ext = "."
+            ext.append($0)
+            return ext
+        }
+
+        return self.filter {
+            // The force unwrap will abort if the element is not a String but this behaviour matches Dawrin, which throws an exception.
+            let filename = $0 as! String
+            for ext in extensions {
+                if filename.hasSuffix(ext) && filename.count > ext.count {
+                    return true
+                }
+            }
+            return false
+        } as! [String]
     }
 
     override open var _cfTypeID: CFTypeID {

TestFoundation/TestNSArray.swift

@@ -51,6 +51,7 @@ class TestNSArray : XCTestCase {
             ("test_insertObjectAtIndex", test_insertObjectAtIndex),
             ("test_insertObjectsAtIndexes", test_insertObjectsAtIndexes),
             ("test_replaceObjectsAtIndexesWithObjects", test_replaceObjectsAtIndexesWithObjects),
+            ("test_pathsMatchingExtensions", test_pathsMatchingExtensions),
         ]
     }
 
@@ -746,6 +747,24 @@ class TestNSArray : XCTestCase {
         XCTAssertEqual(a3, ["a", "b", "c", "d"])
     }
 
+    func test_pathsMatchingExtensions() {
+        let paths = NSArray(arrayLiteral: "file1.txt", "/tmp/file2.txt", "file3.jpg", "file3.png", "/file4.png", "txt", ".txt")
+        let match1 = paths.pathsMatchingExtensions(["txt"])
+        XCTAssertEqual(match1, ["file1.txt", "/tmp/file2.txt"])
+
+        let match2 = paths.pathsMatchingExtensions([])
+        XCTAssertEqual(match2, [])
+
+        let match3 = paths.pathsMatchingExtensions([".txt", "png"])
+        XCTAssertEqual(match3, ["file3.png", "/file4.png"])
+
+        let match4 = paths.pathsMatchingExtensions(["", ".tx", "tx"])
+        XCTAssertEqual(match4, [])
+
+        let match5 = paths.pathsMatchingExtensions(["..txt"])
+        XCTAssertEqual(match5, [])
+    }
+
     private func createTestFile(_ path: String, _contents: Data) -> String? {
         let tempDir = NSTemporaryDirectory() + "TestFoundation_Playground_" + NSUUID().uuidString + "/"
         do {