Swift - Can't import packages - swift

Question

I have been trying out Swift on Ubuntu 20.10 and am having trouble importing packages. Swift is installed properly. I am always getting error: no such module, no matter which package I try.
Here is my Package.swift (Embassy as an example):
// swift-tools-version:5.3
// The swift-tools-version declares the minimum version of Swift required to build this package.
import PackageDescription
let package = Package(
name: "test",
/* products: [
.executable(name: "test", targets: ["test"])
],*/
dependencies: [
// Dependencies declare other packages that this package depends on.
// .package(url: /* package url */, from: "1.0.0"),
.package(url: "https://github.com/envoy/Embassy.git",
from: "4.1.1"),
],
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: "test",
dependencies: []),
.testTarget(
name: "testTests",
dependencies: ["test"]),
]
)
main.swift(under Sources/test)
import Foundation
import Embassy
let loop = try! SelectorEventLoop(selector: try! KqueueSelector())
let server = DefaultHTTPServer(eventLoop: loop, port: 8080) {
(
environ: [String: Any],
startResponse: ((String, [(String, String)]) -> Void),
sendBody: ((Data) -> Void)
) in
// Start HTTP response
startResponse("200 OK", [])
let pathInfo = environ["PATH_INFO"]! as! String
sendBody(Data("the path you're visiting is \(pathInfo.debugDescription)".utf8))
// send EOF
sendBody(Data())
}
// Start HTTP server to listen on the port
try! server.start()
// Run event loop
loop.runForever()

Answer 1

In your Package.swift file you are declaring Embassy as a dependency, but you are not referencing that dependency in any of your targets. In the example you provided, you can alter your package like this:
// swift-tools-version:5.3
// The swift-tools-version declares the minimum version of Swift required to build this package.
import PackageDescription
let package = Package(
name: "test",
dependencies: [
.package(url: "https://github.com/envoy/Embassy.git", from: "4.1.1"),
],
targets: [
// Reference the 'Embassy' package here.
.target(name: "test", dependencies: ["Embassy"]),
.testTarget(name: "testTests", dependencies: ["test", "Embassy"]),
]
)