Add swift-testing package dependency

Author: jmschonfeld

Package.swift

@@ -65,6 +65,9 @@ var dependencies: [Package.Dependency] {
                 branch: "main"),
             .package(
                 url: "https://github.com/swiftlang/swift-syntax",
+                branch: "main"),
+            .package(
+                url: "https://github.com/swiftlang/swift-testing",
                 branch: "main")
         ]
     }
@@ -154,7 +157,8 @@ let package = Package(
             name: "FoundationEssentialsTests",
             dependencies: [
                 "TestSupport",
-                "FoundationEssentials"
+                "FoundationEssentials",
+                .product(name: "Testing", package: "swift-testing")
             ],
             resources: [
                 .copy("Resources")
@@ -191,6 +195,7 @@ let package = Package(
             dependencies: [
                 "TestSupport",
                 "FoundationInternationalization",
+                .product(name: "Testing", package: "swift-testing")
             ],
             swiftSettings: availabilityMacros + featureSettings + testOnlySwiftSettings
         ),
@@ -221,7 +226,8 @@ package.targets.append(contentsOf: [
     .testTarget(
         name: "FoundationMacrosTests",
         dependencies: [
-            "FoundationMacros"
+            "FoundationMacros",
+            .product(name: "Testing", package: "swift-testing")
         ],
         swiftSettings: availabilityMacros + featureSettings + testOnlySwiftSettings
     )