PackageLoadingTests: ensure that we use the correct path spelling (#6510)

Tests here verify the paths, which need the native representation.  This
ensures that we get the correct spelling of the paths in these tests.

The memory leak on the non-Darwin platforms exists due to the path
string not being pushed into an autorelease pool.  The use of
`withUnsafeFileSystemRepresentation` ends up mismatching the arc
separator resulting in a test failure.

Author: compnerd

Tests/PackageLoadingTests/PackageBuilderTests.swift

@@ -1440,8 +1440,14 @@ class PackageBuilderTests: XCTestCase {
                     try TargetDescription(name: "Random", type: .system),
                 ]
             )
+            let map = "/\(predefinedSourceDir)/module.modulemap"
             PackageBuilderTester(manifest, in: fs) { _, diagnostics in
-                diagnostics.check(diagnostic: "package has unsupported layout; missing system target module map at '/\(predefinedSourceDir)/module.modulemap'", severity: .error)
+#if _runtime(_ObjC)
+                diagnostics.check(diagnostic: "package has unsupported layout; missing system target module map at '\(map)'", severity: .error)
+#else
+                // FIXME: there is a memory leak here
+                diagnostics.check(diagnostic: "package has unsupported layout; missing system target module map at '\(String(cString: map.fileSystemRepresentation))'", severity: .error)
+#endif
             }
         }
         do {

Tests/PackageLoadingTests/ToolsVersionParserTests.swift

@@ -161,7 +161,7 @@ class ToolsVersionParserTests: XCTestCase {
 
         XCTAssertThrowsError(
             try ToolsVersionParser.parse(manifestPath: manifestPath, fileSystem: fs),
-            "empty manifest '/lorem/ipsum/dolor/Package.swift'") { error in
+            "empty manifest '\(manifestPath.pathString)'") { error in
                 guard let error = error as? ManifestParseError, case .emptyManifest(let errorPath) = error else {
                     XCTFail("'ManifestParseError.emptyManifest' should've been thrown, but a different error is thrown")
                     return
@@ -172,7 +172,7 @@ class ToolsVersionParserTests: XCTestCase {
                     return
                 }
 
-                XCTAssertEqual(error.description, "'/lorem/ipsum/dolor/Package.swift' is empty")
+                XCTAssertEqual(error.description, "'\(manifestPath._nativePathString(escaped: false))' is empty")
             }
     }