[gardening] Fix update_static_error_tests so it works on Windows.

Change-Id: Ie756cb49468f86abece14c1e15706c5a107e21c3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/450801
Commit-Queue: Alexander Aprelev <[email protected]>
Reviewed-by: Bob Nystrom <[email protected]>

Author: aam

pkg/test_runner/test/update_error_cmdline_test.dart

@@ -73,20 +73,8 @@ Future<void> doTest(List<String> fileNameParts, List<String> testNameParts,
           await run(relativeUriPath, target, expectedLines, expectedUpdateText);
 
       var absoluteNativePath = File(relativeNativePath).absolute.path;
-      var result = await run(
+      errorFound |= await run(
           absoluteNativePath, target, expectedLines, expectedUpdateText);
-      if (Platform.isWindows) {
-        // TODO(johnniwinther,rnystrom): Support absolute paths on Windows.
-        if (!result) {
-          print('Error: Expected failure on Windows. '
-              'Update test to expect success on all platforms.');
-          errorFound = true;
-        } else {
-          print('Error on Windows is expected.');
-        }
-      } else {
-        errorFound |= result;
-      }
     }
 
     if (errorFound) {

pkg/test_runner/tool/update_static_error_tests.dart

@@ -184,10 +184,13 @@ List<TestFile> _listFiles(List<String> pathGlobs,
     // or relative to the current directory.
     var root = pathGlob.startsWith("tests") ? "." : "tests";
 
-    // [Glob] doesn't handle Windows path delimiters, so we normalize it using
-    // [Path]. [Glob] doesn't handle absolute Windows paths, though, so this
-    // only supports the relative paths.
-    pathGlob = Path.normalize(pathGlob);
+    pathGlob = Uri.file(pathGlob).toFilePath(windows: false);
+    if (Platform.isWindows && p.isAbsolute(pathGlob)) {
+      // Trim absolute path's leading forward slash on Windows to accommodate
+      // Glob, which doesn't handle proper backslash-separated Windows paths
+      // and proper absolute file uri on Windows look like '/c:/abc/temp.txt'.
+      pathGlob = pathGlob.substring(1);
+    }
 
     for (var file in Glob(pathGlob, recursive: true).listSync(root: root)) {
       if (file is! File) continue;