CoreML Model in Swift Package Tests

I am trying to create some tests inside a swift package that require the a coreML model. I am trying to copy the compiled model into the working bundle, but when I run the tests, the resource is not found using the Bundle.main.url() method. The project also compiles and runs successfully when running command+b.

My file structure:

My Package.swift:

// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
  name: "AudioPreprocessingSPM",
  products: [
    // Products define the executables and libraries a package produces, and make them visible to other packages.
    .library(
      name: "AudioPreprocessingSPM",
      targets: ["AudioPreprocessingSPM"]),
  ],
  dependencies: [
    // Dependencies declare other packages that this package depends on.
    // .package(url: /* package url */, from: "1.0.0"),
  ],
  targets: [
    // Targets are the basic building blocks of a package. A target can define a module or a test suite.
    // Targets can depend on other targets in this package, and on products in packages this package depends on.
    .target(
      name: "AudioPreprocessingSPM",
      dependencies: [],
      resources: [.copy("A-6.swift"), .copy("A-6.mlmodelc")]),
    .testTarget(
      name: "AudioPreprocessingSPMTests",
      dependencies: ["AudioPreprocessingSPM"],
      resources: [.copy("A-6.swift"), .copy("A-6.mlmodelc")]),
  ]
)

My Package Test:

@testable import AudioPreprocessingSPM


final class AudioEngineTests: XCTestCase {
   
  func testCreateAudioEngineInstance() {
    var model = try! A_6(configuration: .init())
  }
}

My modified A-6.swift file:

class A_6 {
  let model: MLModel

  /// URL of model assuming it was installed in the same bundle as this class
  class var urlOfModelInThisBundle : URL {
    var bundles = Bundle.allBundles.map{ return $0.bundlePath }
     
    return Bundle.main.url(forResource: "A-6", withExtension: "mlmodelc")!
  }

  // Removed unmodified portions of auto generated file below
}

I am not very familiar with how bundling works for a swift package, but I believe that is where the issue lies.

Error Received when running test: Fatal error: Unexpectedly found nil while unwrapping an Optional value: file AudioPreprocessingSPMTests/A-6.swift, line 100 2021-07-04 11:37:21.785589-0400 xctest[79167:2602315] Fatal error: Unexpectedly found nil while unwrapping an Optional value: file AudioPreprocessingSPMTests/A-6.swift, line 100

The default generation of file A-6.swift also fails:

class var urlOfModelInThisBundle : URL {
     
    let bundle = Bundle(for: A_6.self)
     
    return bundle.url(forResource: "A-6", withExtension: "mlmodelc")!
}

Thanks for your help