Pod::Spec.new do |spec|
  spec.name = "MyPod"
  spec.default_subspec = 'Library'

  spec.subspec "Library" do |subspec|
    subspec.source_files = "src/*.swift"
    // ... other cocoapods configuration commands
  end
  spec.subspec "TestDoubles" do |subspec|
    subspec.source_files = "testdoubles/*.swift"
    // ... other cocoapods configuration commands
  end
end

pod 'MyPod'

pod 'MyPod/TestDoubles'