Test image scaling

Tests/SnapshotTestingTests/SnapshotTestingTests.swift

@@ -1133,6 +1133,18 @@ final class SnapshotTestingTests: XCTestCase {
       let firstLine = message?.split(whereSeparator: \.isNewline).first
       XCTAssertEqual(firstLine, "[\(platform)] Snapshot size (123.0, 123.0) is unequal to expected size (100.0, 100.0)")
     }
+
+    func testSnapshotUnscaledByDefault() throws {
+      let size = CGSize(width: 100, height: 100)
+      let view = TestView(size: size)
+      view.backgroundColor = .cyan
+      assertSnapshot(of: view, as: .image)
+      let url = URL(fileURLWithPath: String(#file), isDirectory: false)
+        .deletingLastPathComponent()
+        .appendingPathComponent("__Snapshots__/SnapshotTestingTests/testSnapshotUnscaledByDefault.1.png")
+      let image = try XCTUnwrap(XImage(contentsOf: url))
+      XCTAssertEqual(image.size, size)
+    }
   #endif
 
   #if os(iOS)

Tests/SnapshotTestingTests/TestHelpers.swift

@@ -110,3 +110,34 @@ let osVersion = ProcessInfo.processInfo.operatingSystemVersion
     }
   }
 #endif
+
+#if os(iOS) || os(macOS) || os(tvOS)
+  extension XImage {
+    convenience init?(contentsOf url: URL) {
+      #if os(iOS) || os(tvOS)
+      self.init(contentsOfFile: url.path)
+      #elseif os(macOS)
+      self.init(byReferencing: url)
+      #endif
+    }
+  }
+#endif
+
+class TestView: XView {
+  #if os(macOS)
+  var backgroundColor: NSColor? {
+    get {
+      guard let cgColor = layer?.backgroundColor else { return nil }
+      return NSColor(cgColor: cgColor)
+    }
+    set {
+      wantsLayer = true
+      layer?.backgroundColor = newValue?.cgColor
+    }
+  }
+  #endif
+
+  convenience init(size: CGSize) {
+    self.init(frame: .init(origin: .zero, size: size))
+  }
+}