diff --git a/swift/ql/test/library-tests/dataflow/flowsources/url.swift b/swift/ql/test/library-tests/dataflow/flowsources/url.swift
new file mode 100644
index 00000000000..0eab68736ce
--- /dev/null
+++ b/swift/ql/test/library-tests/dataflow/flowsources/url.swift
@@ -0,0 +1,76 @@
+// --- stubs ---
+
+struct URL {
+	init?(string: String) {}
+
+	struct AsyncBytes : AsyncSequence, AsyncIteratorProtocol {
+		typealias Element = UInt8
+
+		func makeAsyncIterator() -> AsyncBytes {
+			return AsyncBytes()
+		}
+
+		mutating func next() async -> Element? { return nil }
+
+		var lines: AsyncLineSequence<Self> {
+			get {
+				return AsyncLineSequence<Self>()
+			}
+		}
+	}
+
+	var resourceBytes: URL.AsyncBytes {
+		get {
+			return AsyncBytes()
+		}
+	}
+
+	struct AsyncLineSequence<Base> : AsyncSequence, AsyncIteratorProtocol where Base : AsyncSequence, Base.Element == UInt8 {
+		typealias Element = String
+
+		func makeAsyncIterator() -> AsyncLineSequence<Base> {
+			return AsyncLineSequence<Base>()
+		}
+
+		mutating func next() async -> Element? { return nil }
+	}
+
+	var lines: AsyncLineSequence<URL.AsyncBytes> {
+		get {
+			return AsyncLineSequence<URL.AsyncBytes>()
+		}
+	}
+}
+
+func print(_ items: Any...) {}
+
+// --- tests ---
+
+func testURLs() async {
+	do
+	{
+		let url = URL(string: "http://example.com/")!
+		let bytes = url.resourceBytes // SOURCE
+
+		for try await byte in bytes
+		{
+			print(byte)
+		}
+
+		let lines = url.lines // SOURCE
+
+		for try await line in lines
+		{
+			print(line)
+		}
+
+		let lines2 = bytes.lines // SOURCE
+
+		for try await line in lines2
+		{
+			print(line)
+		}
+	} catch {
+		// ...
+	}
+}