Skip testWasm in CI if toolchain cannot compile for wasm

Not all CI jobs are capable of building for wasm, so we should be able to skip this job in Swift CI.

Author: ahoppen

Sources/SKTestSupport/SkipUnless.swift

@@ -84,6 +84,7 @@ package actor SkipUnless {
   }
 
   private func skipUnlessSupported(
+    allowSkippingInCI: Bool = false,
     featureName: String = #function,
     file: StaticString,
     line: UInt,
@@ -92,8 +93,8 @@ package actor SkipUnless {
     let checkResult: FeatureCheckResult
     if let cachedResult = checkCache[featureName] {
       checkResult = cachedResult
-    } else if ProcessEnv.block["SWIFTCI_USE_LOCAL_DEPS"] != nil {
-      // Never skip tests in CI. Toolchain should be up-to-date
+    } else if ProcessEnv.block["SWIFTCI_USE_LOCAL_DEPS"] != nil && !allowSkippingInCI {
+      // In general, don't skip tests in CI. Toolchain should be up-to-date
       checkResult = .featureSupported
     } else {
       checkResult = try await featureCheck()
@@ -466,7 +467,7 @@ package actor SkipUnless {
     file: StaticString = #filePath,
     line: UInt = #line
   ) async throws {
-    return try await shared.skipUnlessSupportedByToolchain(swiftVersion: SwiftVersion(6, 0), file: file, line: line) {
+    return try await shared.skipUnlessSupported(allowSkippingInCI: true, file: file, line: line) {
       let swiftFrontend = try await unwrap(ToolchainRegistry.forTesting.default?.swift).parentDirectory
         .appending(component: "swift-frontend")
       return try await withTestScratchDir { scratchDirectory in
@@ -489,7 +490,10 @@ package actor SkipUnless {
         )
         try process.launch()
         let result = try await process.waitUntilExit()
-        return result.exitStatus == .terminated(code: 0)
+        if result.exitStatus == .terminated(code: 0) {
+          return .featureSupported
+        }
+        return .featureUnsupported(skipMessage: "Skipping because toolchain can not compile for wasm")
       }
     }
   }