Defined the library and tests targets in the Package file.

Package.swift

@@ -3,21 +3,34 @@
 import PackageDescription
 
 let package = Package(
-    name: "amiibo-api",
+    name: AmiiboAPI.package,
     products: [
-        // Products define the executables and libraries a package produces, making them visible to other packages.
         .library(
-            name: "amiibo-api",
+            name: AmiiboAPI.package,
-            targets: ["amiibo-api"]),
+            targets: [
+                AmiiboAPI.target
+            ]
+        )
     ],
     targets: [
-        // Targets are the basic building blocks of a package, defining a module or a test suite.
-        // Targets can depend on other targets in this package and products from dependencies.
         .target(
-            name: "amiibo-api"),
+            name: AmiiboAPI.target,
+            path: "Sources"
+        ),
         .testTarget(
-            name: "amiibo-apiTests",
+            name: AmiiboAPI.test,
-            dependencies: ["amiibo-api"]
+            dependencies: [
+                .byName(name: AmiiboAPI.target)
+            ],
+            path: "Tests"
         ),
     ]
 )
+
+// MARK: - Constants
+
+enum AmiiboAPI {
+    static let package = "amiibo-api"
+    static let target = "AmiiboAPI"
+    static let test = "\(AmiiboAPI.target)Tests"
+}

Tests/amiibo_apiTests.swift

@@ -1,5 +1,6 @@
 import Testing
-@testable import amiibo_api
+
+@testable import AmiiboAPI
 
 @Test func example() async throws {
     // Write your test here and use APIs like `#expect(...)` to check expected conditions.