When I try running ‘swift test’ in my terminal, there was an error saying a dependency doesn’t have a product for MacOS, or something like that. I was confused because my package is declared for iOS platform only, in the manifest file.
Can you post that bit of your manifest? I’m not sure that you can do that using the platforms parameter. If you list some platforms and don’t list others, it just means ‘use the default supported platform versions’ for the unlisted platforms. (The name is somewhat confusing.)