Unit tests don't compile on Windows

[valeriyvan]

swift run PNGTests
Building for debugging...
c:\Users\1\Documents\tmp1\swift-png\Tests\PNG\Main.swift:9:1: error: 'main' attribute cannot be used in a module that contains top-level code
@main
^
c:\Users\1\Documents\tmp1\swift-png\Tests\PNG\Main.swift:1:1: note: top-level code defined in this source file
@testable import PNG
^
c:\Users\1\Documents\tmp1\swift-png\Tests\PNG\Main.swift:9:1: error: 'main' attribute cannot be used in a module that contains top-level code
@main
^
c:\Users\1\Documents\tmp1\swift-png\Tests\PNG\Main.swift:1:1: note: top-level code defined in this source file
@testable import PNG
^

Version of swift:

swift --version
compnerd.org Swift version 5.7.1 (swift-5.7.1-RELEASE)
Target: x86_64-unknown-windows-msvc

These unit tests build and run on macOS normally. Version of swift on macOS is the same as on Windows.

[tayloraswift]

can you test if this also occurs with 5.6.2? (that is what the CI uses)

also, does -parse-as-library help?

[valeriyvan]

can you test if this also occurs with 5.6.2? (that is what the CI uses)

for me it was so hard to make swift on WIndows up and running, that I am affraid to install older version along with latest.

also, does -parse-as-library help?

swift -parse-as-library run PNGTests
error: option '-parse-as-library' is not supported by 'swift'; did you mean to use 'swiftc'?