diff --git a/pkgs/test/CHANGELOG.md b/pkgs/test/CHANGELOG.md
index 1d2bf5f37..6ab538aef 100644
--- a/pkgs/test/CHANGELOG.md
+++ b/pkgs/test/CHANGELOG.md
@@ -3,6 +3,8 @@
 * Drop support for null unsafe Dart, bump SDK constraint to `3.0.0`.
 * Make some annotation classes `final`: `OnPlatform`, `Retry`, `Skip`, `Tags`,
   `TestOn`, `Timeout`.
+* Fix the `root_` fields in the JSON reporter when running a test on Windows
+  with an absolute path.
 
 ## 1.24.3
 
diff --git a/pkgs/test/test/runner/json_reporter_test.dart b/pkgs/test/test/runner/json_reporter_test.dart
index b6b3317d7..934d89a63 100644
--- a/pkgs/test/test/runner/json_reporter_test.dart
+++ b/pkgs/test/test/runner/json_reporter_test.dart
@@ -512,7 +512,7 @@ void main() {
           args: ['-p', 'chrome']);
     }, tags: ['chrome'], skip: 'https://github.com/dart-lang/test/issues/872');
 
-    test('the root suite if applicable', () {
+    test('the root suite from a relative path', () {
       return _expectReport(
           '''
       customTest('success 1', () {});
@@ -543,6 +543,46 @@ void main() {
             'common.dart': '''
 import 'package:test/test.dart';
 
+void customTest(String name, dynamic Function() testFn) => test(name, testFn);
+''',
+          });
+    });
+
+    test('the root suite from an absolute path', () {
+      final path = p.prettyUri(p.join(d.sandbox, 'test.dart'));
+      return _expectReport(
+          '''
+      customTest('success 1', () {});
+      test('success 2', () {});
+    ''',
+          useRelativePath: false,
+          [
+            [
+              suiteJson(0, path: equalsIgnoringCase(path)),
+              testStartJson(
+                  1, allOf(startsWith('loading '), endsWith('test.dart')),
+                  groupIDs: []),
+              testDoneJson(1, hidden: true),
+            ],
+            [
+              groupJson(2, testCount: 2),
+              testStartJson(3, 'success 1',
+                  line: 3,
+                  column: 60,
+                  url: p.toUri(p.join(d.sandbox, 'common.dart')).toString(),
+                  rootColumn: 7,
+                  rootLine: 7,
+                  rootUrl: p.toUri(p.join(d.sandbox, 'test.dart')).toString()),
+              testDoneJson(3),
+              testStartJson(4, 'success 2', line: 8, column: 7),
+              testDoneJson(4),
+            ]
+          ],
+          doneJson(),
+          externalLibraries: {
+            'common.dart': '''
+import 'package:test/test.dart';
+
 void customTest(String name, dynamic Function() testFn) => test(name, testFn);
 ''',
           });
@@ -586,6 +626,7 @@ void customTest(String name, dynamic Function() testFn) => test(name, testFn);
 Future<void> _expectReport(String tests,
     List<List<Object /*Map|Matcher*/ >> expected, Map<Object, Object> done,
     {List<String> args = const [],
+    bool useRelativePath = true,
     Map<String, String> externalLibraries = const {}}) async {
   var testContent = StringBuffer('''
 import 'dart:async';
@@ -603,8 +644,9 @@ import 'package:test/test.dart';
     ..writeln('}');
 
   await d.file('test.dart', testContent.toString()).create();
+  var testPath = useRelativePath ? 'test.dart' : p.join(d.sandbox, 'test.dart');
 
-  var test = await runTest(['test.dart', '--chain-stack-traces', ...args],
+  var test = await runTest([testPath, '--chain-stack-traces', ...args],
       reporter: 'json');
   await test.shouldExit();
 
diff --git a/pkgs/test/test/runner/json_reporter_utils.dart b/pkgs/test/test/runner/json_reporter_utils.dart
index c53562bf5..bbdbb78f0 100644
--- a/pkgs/test/test/runner/json_reporter_utils.dart
+++ b/pkgs/test/test/runner/json_reporter_utils.dart
@@ -61,15 +61,16 @@ Map<String, Object> _allSuitesJson({int count = 1}) =>
 /// Returns the event emitted by the JSON reporter indicating that a suite has
 /// begun running.
 ///
-/// The [platform] defaults to `"vm"`, the [path] defaults to `"test.dart"`.
+/// The [platform] defaults to `'vm'`.
+/// The [path] defaults to `equals('test.dart')`.
 Map<String, Object> suiteJson(int id,
-        {String platform = 'vm', String path = 'test.dart'}) =>
+        {String platform = 'vm', Matcher? path}) =>
     {
       'type': 'suite',
       'suite': {
         'id': id,
         'platform': platform,
-        'path': path,
+        'path': path ?? 'test.dart',
       }
     };
 
@@ -120,7 +121,7 @@ Map<String, Object> groupJson(int id,
 /// [skip] is `true`, the test is expected to be marked as skipped without a
 /// reason. If it's a [String], the test is expected to be marked as skipped
 /// with that reason.
-Map<String, Object> testStartJson(int id, String name,
+Map<String, Object> testStartJson(int id, Object /*String|Matcher*/ name,
     {int? suiteID,
     Iterable<int>? groupIDs,
     int? line,
diff --git a/pkgs/test_core/CHANGELOG.md b/pkgs/test_core/CHANGELOG.md
index a5ff68161..e80bfbfd3 100644
--- a/pkgs/test_core/CHANGELOG.md
+++ b/pkgs/test_core/CHANGELOG.md
@@ -3,6 +3,8 @@
 * Drop support for null unsafe Dart, bump SDK constraint to `3.0.0`.
 * Add `final` modifier on some implementation classes: `Configuration`,
   `CustomRuntime`,`RuntimeSettings`, `SuiteConfiguration`. 
+* Fix the `root_` fields in the JSON reporter when running a test on Windows
+  with an absolute path.
 
 ## 0.5.3
 
diff --git a/pkgs/test_core/lib/src/runner/reporter/json.dart b/pkgs/test_core/lib/src/runner/reporter/json.dart
index 549781753..0683b60b9 100644
--- a/pkgs/test_core/lib/src/runner/reporter/json.dart
+++ b/pkgs/test_core/lib/src/runner/reporter/json.dart
@@ -303,7 +303,7 @@ class JsonReporter implements Reporter {
   /// all be `null`.
   Map<String, dynamic> _frameInfo(SuiteConfiguration suiteConfig, Trace? trace,
       Runtime runtime, String suitePath) {
-    var absoluteSuitePath = p.absolute(suitePath);
+    var absoluteSuitePath = p.canonicalize(p.absolute(suitePath));
     var frame = trace?.frames.first;
     if (frame == null || (suiteConfig.jsTrace && runtime.isJS)) {
       return {'line': null, 'column': null, 'url': null};
@@ -311,7 +311,7 @@ class JsonReporter implements Reporter {
 
     var rootFrame = trace?.frames.firstWhereOrNull((frame) =>
         frame.uri.scheme == 'file' &&
-        frame.uri.toFilePath() == absoluteSuitePath);
+        p.canonicalize(frame.uri.toFilePath()) == absoluteSuitePath);
     return {
       'line': frame.line,
       'column': frame.column,