Tests: enable a test and update skip reason

Tests/BasicsTests/Serialization/SerializedJSONTests.swift

@@ -34,7 +34,7 @@ final class SerializedJSONTests: XCTestCase {
     }
 
     func testPathInterpolationFailsOnWindows() throws {
-        try skipOnWindowsAsTestCurrentlyFails(because: "Expectations are not met")
+        try skipOnWindowsAsTestCurrentlyFails(because: "Expectations are not met. Possibly related to https://github.com/swiftlang/swift-package-manager/issues/8511")
 
 #if os(Windows)
         var path = try AbsolutePath(validating: #"\\?\C:\Users"#)

Tests/BuildTests/BuildSystemDelegateTests.swift

@@ -30,7 +30,7 @@ final class BuildSystemDelegateTests: XCTestCase {
     }
 
     func testFilterNonFatalCodesignMessages() async throws {
-        try skipOnWindowsAsTestCurrentlyFails(because: "Package fails to build when the test is being executed")
+        try skipOnWindowsAsTestCurrentlyFails(because: "https://github.com/swiftlang/swift-package-manager/issues/8540: Package fails to build when the test is being executed")
 
         try XCTSkipIf(!UserToolchain.default.supportsSDKDependentTests(), "skipping because test environment doesn't support this test")
         // Note: we can re-use the `TestableExe` fixture here since we just need an executable.

Tests/PackageGraphTests/ModulesGraphTests.swift

@@ -23,7 +23,7 @@ import struct TSCBasic.ByteString
 
 final class ModulesGraphTests: XCTestCase {
     func testBasic() throws {
-        try skipOnWindowsAsTestCurrentlyFails()
+        try skipOnWindowsAsTestCurrentlyFails(because: "Possibly related to: https://github.com/swiftlang/swift-package-manager/issues/8511")
         let fs = InMemoryFileSystem(
             emptyFiles:
             "/Foo/Sources/Foo/source.swift",

Tests/PackageLoadingTests/PackageBuilderTests.swift

@@ -564,7 +564,7 @@ final class PackageBuilderTests: XCTestCase {
     }
 
     func testTestManifestSearch() throws {
-        try skipOnWindowsAsTestCurrentlyFails()
+        try skipOnWindowsAsTestCurrentlyFails(because: "possibly related to https://github.com/swiftlang/swift-package-manager/issues/8511")
 
         let fs = InMemoryFileSystem(emptyFiles:
             "/pkg/foo.swift",

Tests/PackageModelTests/PackageModelTests.swift

@@ -17,7 +17,6 @@ import Basics
 
 import func TSCBasic.withTemporaryFile
 import XCTest
-import _InternalTestSupport // for skipOnWindowsAsTestCurrentlyFails
 
 import struct TSCBasic.ByteString
 
@@ -160,10 +159,7 @@ final class PackageModelTests: XCTestCase {
     }
 
     func testDetermineSwiftCompilers() throws {
-        try skipOnWindowsAsTestCurrentlyFails()
-
         let fs = localFileSystem
-        try withTemporaryFile { _ in
             try withTemporaryDirectory(removeTreeOnDeinit: true) { tmp in
                 // When swiftc is not in the toolchain bin directory, UserToolchain
                 // should find it in the system PATH search paths in the order they
@@ -175,10 +171,17 @@ final class PackageModelTests: XCTestCase {
 
                 // Create a directory with two swiftc binaries in it.
                 let binDirs = ["bin1", "bin2"].map { tmp.appending($0) }
+                #if os(Windows)
+                let exeSuffix = ".exe"
+                #else
+                let exeSuffix = ""
+                #endif
+                let expectedExecuable = "swiftc\(exeSuffix)" // Files that end with .exe are considered executable on Windows.
                 for binDir in binDirs {
                     try fs.createDirectory(binDir)
-                    let binFile = binDir.appending("swiftc")
+                    let binFile = binDir.appending(expectedExecuable)
                     try fs.writeFileContents(binFile, bytes: ByteString(Self.tinyPEBytes))
+                    XCTAssertTrue(fs.exists(binFile), "File '\(binFile)' does not exist when it should")
                     #if !os(Windows)
                     try fs.chmod(.executable, path: binFile, options: [])
                     #endif
@@ -193,8 +196,7 @@ final class PackageModelTests: XCTestCase {
                 )
 
                 // The first swiftc in the search paths should be chosen.
-                XCTAssertEqual(compilers.compile, binDirs.first?.appending("swiftc"))
+                XCTAssertEqual(compilers.compile, binDirs.first?.appending(expectedExecuable))
             }
-        }
     }
 }

Tests/QueryEngineTests/QueryEngineTests.swift

@@ -100,7 +100,7 @@ private struct Expression: CachingQuery {
 
 final class QueryEngineTests: XCTestCase {
   func testFilePathHashing() throws {
-    try skipOnWindowsAsTestCurrentlyFails()
+    try skipOnWindowsAsTestCurrentlyFails(because: "https://github.com/swiftlang/swift-package-manager/issues/8541")
 
     let path = "/root"