Some args cleanup

Author: grynspan

Sources/Build/LLBuildCommands.swift

@@ -249,27 +249,27 @@ final class TestEntryPointCommand: CustomLLBuildCommand, TestBuildCommand {
             @main
             @available(*, deprecated, message: "Not actually deprecated. Marked as deprecated to allow inclusion of deprecated tests (which test deprecated functionality) without warnings")
             struct Runner {
-                static func which() -> String {
-                    // HACK: abstract this check properly!
-                    let args = CommandLine.arguments
-                    if args.contains("--testing-library=swift-testing") {
-                        return "swift-testing" 
-                    } else if args.contains("--testing-library=xctest") {
-                        return "XCTest"
+                private static func testingLibrary() -> String {
+                    var iterator = CommandLine.arguments.makeIterator()
+                    while let argument = iterator.next() {
+                        if argument == "--testing-library", let libraryName = iterator.next() {
+                            return libraryName.lowercased()
+                        }
                     }
+
                     // Fallback if not specified: run XCTest (legacy behavior)
-                    return "XCTest"
+                    return "xctest"
                 }
 
                 static func main() async {
-                    let which = Self.which()
+                    let testingLibrary = Self.testingLibrary()
             #if \#(swiftTestingImportCondition)
-                    if which == "swift-testing" {
+                    if testingLibrary == "swift-testing" {
                         await Testing.__swiftPMEntryPoint() as Never
                     }
             #endif
             #if \#(xctestImportCondition)
-                    if which == "XCTest" {
+                    if testingLibrary == "xctest" {
                         \#(testObservabilitySetup)
             #if os(WASI)
                         /// On WASI, we can't block the main thread, so XCTestMain is defined as async.

Sources/Commands/SwiftTestCommand.swift

@@ -401,7 +401,6 @@ public struct SwiftTestCommand: AsyncSwiftCommand {
         // Pass through all arguments from the command line to Swift Testing.
         var additionalArguments = additionalArguments
         if library == .swiftTesting {
-            additionalArguments += ["--"]
             additionalArguments += CommandLine.arguments.dropFirst()
         }
 
@@ -678,7 +677,7 @@ extension SwiftTestCommand {
             }
 
             if testLibraryOptions.isEnabled(.swiftTesting) {
-                let additionalArguments = ["--", "--list-tests"] + CommandLine.arguments.dropFirst()
+                let additionalArguments = ["--list-tests"] + CommandLine.arguments.dropFirst()
                 let runner = TestRunner(
                     bundlePaths: testProducts.map(\.bundlePath),
                     additionalArguments: additionalArguments,
@@ -837,7 +836,7 @@ final class TestRunner {
         if library == .swiftTesting {
             // HACK: tell the test bundle/executable that we want to run Swift Testing, not XCTest.
             // XCTest doesn't understand this argument (yet), so don't pass it there.
-            args += ["--testing-library=swift-testing"]
+            args += ["--testing-library", "swift-testing"]
         }
 
         return args