diff --git a/pkg/analysis_server/test/abstract_context.dart b/pkg/analysis_server/test/abstract_context.dart
index a7ec58319e3..bae688b242f 100644
--- a/pkg/analysis_server/test/abstract_context.dart
+++ b/pkg/analysis_server/test/abstract_context.dart
@@ -34,7 +34,7 @@ class AbstractContextTest
   static final ByteStore _byteStore = MemoryByteStore();
 
   /// Whether to rewrite line endings in test code based on platform.
-  bool useLineEndingsForPlatform = false;
+  bool useLineEndingsForPlatform = true;
 
   final Map<String, String> _declaredVariables = {};
   AnalysisContextCollectionImpl? _analysisContextCollection;
diff --git a/pkg/analysis_server/test/lsp/source_edits_test.dart b/pkg/analysis_server/test/lsp/source_edits_test.dart
index 8ca9e497f16..1066390a7bb 100644
--- a/pkg/analysis_server/test/lsp/source_edits_test.dart
+++ b/pkg/analysis_server/test/lsp/source_edits_test.dart
@@ -3,10 +3,12 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:convert';
+import 'dart:io';
 
 import 'package:analysis_server/lsp_protocol/protocol.dart';
 import 'package:analysis_server/src/lsp/error_or.dart';
 import 'package:analysis_server/src/lsp/source_edits.dart';
+import 'package:analyzer/src/test_utilities/test_code_format.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ -319,13 +321,14 @@ Delete 1:24-1:26
   /// https://github.com/Dart-Code/Dart-Code/issues/5200
   Future<void> test_minimalEdits_comment_multiLine_trailingWhitespace() async {
     // The initial content has a trailing space on the end of the comment.
-    const startContent = r'''
+    var startContent =
+        TestCode.parse(r'''
 /**
- * line with trailing whitespace 
- * line with trailing whitespace 
+ * line with trailing whitespace /**/
+ * line with trailing whitespace /**/
  */
 int? a;
-''';
+''').code;
     // We expect the trailing spaces to be removed.
     const endContent = r'''
 /**
@@ -619,6 +622,9 @@ void g() {
     String? expectedFormatResult,
     Range? range,
   }) async {
+    start = normalizeSource(start);
+    end = normalizeSource(end);
+
     await parseTestCode(start);
     var edits =
         generateEditsForFormatting(testParsedResult, range: range).result!;
@@ -639,10 +645,26 @@ void g() {
     String? expectedFormatResult,
     Range? range,
   }) async {
-    start = start.trim();
-    end = end.trim();
+    start = normalizeSource(start.trim());
+    end = normalizeSource(end.trim());
+    if (expectedFormatResult != null) {
+      expectedFormatResult = normalizeSource(expectedFormatResult.trim());
+    }
     expected = expected.trim();
-    expectedFormatResult = expectedFormatResult?.trim();
+
+    // Expectation descriptions are always written with literal newlines as '\n'
+    // so on Windows we will need to update the expectation to '\r\n' before
+    // comparing.
+    expect(
+      expected,
+      isNot(contains(r'\r')),
+      reason:
+          'Expectations should always be written with literal '
+          r"'\n' to indicate newlines regardless of platform",
+    );
+    if (Platform.isWindows) {
+      expected = expected.replaceAll(r'\n', r'\r\n');
+    }
 
     await parseTestCode(start);
     var edits = generateMinimalEdits(testParsedResult, end, range: range);
diff --git a/pkg/analysis_server/test/services/completion/postfix/postfix_completion_test.dart b/pkg/analysis_server/test/services/completion/postfix/postfix_completion_test.dart
index 1d244bc0e50..653eefdd48b 100644
--- a/pkg/analysis_server/test/services/completion/postfix/postfix_completion_test.dart
+++ b/pkg/analysis_server/test/services/completion/postfix/postfix_completion_test.dart
@@ -37,7 +37,7 @@ class PostfixCompletionTest extends AbstractSingleUnitTest {
     if (change.edits.isNotEmpty) {
       // We use a carat in the expected code to prevent lines containing only
       // whitespace from being made empty.
-      var expectedCode = TestCode.parse(expected);
+      var expectedCode = TestCode.parse(normalizeSource(expected));
       var resultCode = SourceEdit.applySequence(
         testCode,
         change.edits[0].edits,
@@ -68,7 +68,7 @@ class PostfixCompletionTest extends AbstractSingleUnitTest {
   }
 
   Future<void> _prepareProcessor(String key, String code) async {
-    testCodeCode = TestCode.parse(code);
+    testCodeCode = TestCode.parse(normalizeSource(code));
 
     verifyNoTestUnitErrors = false;
     await resolveTestCode(testCodeCode.code);
diff --git a/pkg/analysis_server/test/services/correction/organize_directives_test.dart b/pkg/analysis_server/test/services/correction/organize_directives_test.dart
index ab55929b8bc..160685765f0 100644
--- a/pkg/analysis_server/test/services/correction/organize_directives_test.dart
+++ b/pkg/analysis_server/test/services/correction/organize_directives_test.dart
@@ -1001,7 +1001,7 @@ class NonLibraryAnnotation {
     );
     var edits = organizer.organize();
     var result = SourceEdit.applySequence(testCode, edits);
-    expect(result, expectedCode);
+    expect(result, normalizeSource(expectedCode));
   }
 
   Future<void> _computeUnitAndErrors(String code) async {
diff --git a/pkg/analysis_server/test/services/correction/sort_members_test.dart b/pkg/analysis_server/test/services/correction/sort_members_test.dart
index 71b11f863c4..7e933b4057c 100644
--- a/pkg/analysis_server/test/services/correction/sort_members_test.dart
+++ b/pkg/analysis_server/test/services/correction/sort_members_test.dart
@@ -1793,6 +1793,6 @@ void f() {}
     );
     var edits = sorter.sort();
     var result = SourceEdit.applySequence(testCode, edits);
-    expect(result, expectedCode);
+    expect(result, normalizeSource(expectedCode));
   }
 }
diff --git a/pkg/analysis_server/test/src/computer/color_computer_test.dart b/pkg/analysis_server/test/src/computer/color_computer_test.dart
index 836b4fdb768..9bf9c7d91cb 100644
--- a/pkg/analysis_server/test/src/computer/color_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/color_computer_test.dart
@@ -137,8 +137,9 @@ class ColorComputerTest extends AbstractContextTest {
     Map<String, int> expectedColorValues, {
     String? otherCode,
   }) async {
-    dartCode = _withCommonImports(dartCode);
-    otherCode = otherCode != null ? _withCommonImports(otherCode) : null;
+    dartCode = _withCommonImportsNormalized(dartCode);
+    otherCode =
+        otherCode != null ? _withCommonImportsNormalized(otherCode) : null;
 
     newFile(testPath, dartCode);
     if (otherCode != null) {
@@ -460,10 +461,12 @@ final a = [[COLOR]];
     await checkAllColors(testCode);
   }
 
-  String _withCommonImports(String code) => '''
+  String _withCommonImportsNormalized(String code) {
+    return normalizeSource('''
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/painting.dart';
 import 'package:flutter/material.dart';
 
-$code''';
+$code''');
+  }
 }
diff --git a/pkg/analysis_server/test/src/computer/folding_computer_test.dart b/pkg/analysis_server/test/src/computer/folding_computer_test.dart
index bcd0a67bd38..8ee9b5d4ee4 100644
--- a/pkg/analysis_server/test/src/computer/folding_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/folding_computer_test.dart
@@ -1041,7 +1041,7 @@ void f() {}
   }
 
   Future<void> _computeRegions(String sourceContent) async {
-    code = TestCode.parse(sourceContent);
+    code = TestCode.parse(normalizeSource(sourceContent));
     var file = newFile(sourcePath, code.code);
     var result = await getResolvedUnit(file);
     var computer = DartUnitFoldingComputer(result.lineInfo, result.unit);
diff --git a/pkg/analysis_server/test/src/computer/highlights_computer_test.dart b/pkg/analysis_server/test/src/computer/highlights_computer_test.dart
index aa91353ce1d..ca711fafd93 100644
--- a/pkg/analysis_server/test/src/computer/highlights_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/highlights_computer_test.dart
@@ -110,7 +110,7 @@ void f() {
     String content, {
     bool hasErrors = false,
   }) async {
-    this.content = content;
+    this.content = content = normalizeSource(content);
     var file = newFile(sourcePath, content);
     var result = await getResolvedUnit(file);
 
diff --git a/pkg/analysis_server/test/src/services/completion/dart/feature_computer_test.dart b/pkg/analysis_server/test/src/services/completion/dart/feature_computer_test.dart
index 5da946fde02..3e9e88728c1 100644
--- a/pkg/analysis_server/test/src/services/completion/dart/feature_computer_test.dart
+++ b/pkg/analysis_server/test/src/services/completion/dart/feature_computer_test.dart
@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analysis_server/src/services/completion/dart/feature_computer.dart';
-import 'package:analyzer/src/test_utilities/test_code_format.dart';
 import 'package:analyzer_plugin/src/utilities/completion/completion_target.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ -1096,11 +1095,8 @@ abstract class FeatureComputerTest extends AbstractSingleUnitTest {
   bool verifyNoTestUnitErrors = false;
 
   Future<void> completeIn(String content) async {
-    var code = TestCode.parse(content);
-    cursorIndex = code.position.offset;
-
-    content = code.code;
-    await resolveTestCode(code.code);
+    await resolveTestCode(content);
+    cursorIndex = parsedTestCode.position.offset;
     completionTarget = CompletionTarget.forOffset(testUnit, cursorIndex);
   }
 }
diff --git a/pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart b/pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart
index 1ff78494511..99acd4088a0 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart
@@ -71,13 +71,13 @@ abstract class AssistProcessorTest extends AbstractSingleUnitTest {
     int index = 0,
   }) async {
     _setPositionOrRange(index);
-    if (useLineEndingsForPlatform) {
-      expected = normalizeNewlinesForPlatform(expected);
-      additionallyChangedFiles = additionallyChangedFiles?.map(
-        (key, value) =>
-            MapEntry(key, value.map(normalizeNewlinesForPlatform).toList()),
-      );
-    }
+
+    expected = normalizeNewlinesForPlatform(expected);
+    additionallyChangedFiles = additionallyChangedFiles?.map(
+      (key, value) =>
+          MapEntry(key, value.map(normalizeNewlinesForPlatform).toList()),
+    );
+
     // Remove any marker in the expected code. We allow markers to prevent an
     // otherwise empty line from having the leading whitespace be removed.
     expected = TestCode.parse(expected).code;
@@ -139,12 +139,6 @@ abstract class AssistProcessorTest extends AbstractSingleUnitTest {
     }).toList();
   }
 
-  @override
-  void setUp() {
-    super.setUp();
-    useLineEndingsForPlatform = true;
-  }
-
   /// Computes assists and verifies that there is an assist of the given kind.
   Future<Assist> _assertHasAssist() async {
     var assists = await _computeAssists();
diff --git a/pkg/analysis_server/test/src/services/correction/fix/fix_processor.dart b/pkg/analysis_server/test/src/services/correction/fix/fix_processor.dart
index 7aedfd32439..ed8467113d0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/fix_processor.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/fix_processor.dart
@@ -113,7 +113,7 @@ abstract class BulkFixProcessorTest extends AbstractSingleUnitTest {
     var fixes = (await processor.fixPubspec([analysisContext])).edits;
     var edits = [for (var fix in fixes) ...fix.edits];
     var result = SourceEdit.applySequence(original, edits);
-    expect(result, expected);
+    expect(result, normalizeSource(expected));
   }
 
   Future<void> assertFormat(String expectedCode) async {
@@ -124,7 +124,7 @@ abstract class BulkFixProcessorTest extends AbstractSingleUnitTest {
     var fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     resultCode = SourceEdit.applySequence(testCode, change.edits[0].edits);
-    expect(resultCode, expectedCode);
+    expect(resultCode, normalizeSource(expectedCode));
   }
 
   Future<void> assertHasFix(String expected, {bool isParse = false}) async {
@@ -136,7 +136,7 @@ abstract class BulkFixProcessorTest extends AbstractSingleUnitTest {
 
     var fileContent = testCode;
     resultCode = SourceEdit.applySequence(fileContent, change.edits[0].edits);
-    expect(resultCode, expected);
+    expect(resultCode, normalizeSource(expected));
   }
 
   Future<void> assertNoFix() async {
@@ -153,7 +153,7 @@ abstract class BulkFixProcessorTest extends AbstractSingleUnitTest {
     var fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     resultCode = SourceEdit.applySequence(testCode, change.edits[0].edits);
-    expect(resultCode, expectedCode);
+    expect(resultCode, normalizeSource(expectedCode));
   }
 
   /// Computes fixes for the specified [testUnit].
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_decorated_box_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_decorated_box_test.dart
index 7bafb5a84d3..b17dd6cd1b0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_decorated_box_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_decorated_box_test.dart
@@ -307,8 +307,6 @@ void f() {
   }
 
   Future<void> test_hierarchy() async {
-    useLineEndingsForPlatform = false;
-
     await resolveTestCode('''
 import 'package:flutter/material.dart';
 
diff --git a/pkg/analysis_server/test/src/services/flutter/widget_description.dart b/pkg/analysis_server/test/src/services/flutter/widget_description.dart
index bb5cd399edc..ff5f8cf88a3 100644
--- a/pkg/analysis_server/test/src/services/flutter/widget_description.dart
+++ b/pkg/analysis_server/test/src/services/flutter/widget_description.dart
@@ -27,7 +27,7 @@ class WidgetDescriptionBase extends AbstractSingleUnitTest {
       testAnalysisResult.content,
       fileEdit.edits,
     );
-    expect(actual, expected);
+    expect(actual, normalizeSource(expected));
   }
 
   void assertPropertyJsonText(
diff --git a/pkg/analysis_server/test/src/utilities/extensions/ast_test.dart b/pkg/analysis_server/test/src/utilities/extensions/ast_test.dart
index 3e6919a0991..9e14c5d9edf 100644
--- a/pkg/analysis_server/test/src/utilities/extensions/ast_test.dart
+++ b/pkg/analysis_server/test/src/utilities/extensions/ast_test.dart
@@ -178,7 +178,7 @@ class C {}
   void _assertTokens(List<String> expected) {
     expect(
       result.unit.fileHeader.map((token) => token.lexeme),
-      orderedEquals(expected),
+      orderedEquals(expected.map(normalizeSource)),
     );
   }
 }
diff --git a/pkg/analysis_server/test/src/utilities/selection_test.dart b/pkg/analysis_server/test/src/utilities/selection_test.dart
index ac09d0681c5..ab8d88ec660 100644
--- a/pkg/analysis_server/test/src/utilities/selection_test.dart
+++ b/pkg/analysis_server/test/src/utilities/selection_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:io';
+
 import 'package:analysis_server_plugin/src/utilities/selection.dart';
 import 'package:analyzer/src/test_utilities/test_code_format.dart';
 import 'package:test/test.dart';
@@ -1409,6 +1411,20 @@ nodesInRange
   void _assertSelection(_CodeSelection selection, String expected) {
     var buffer = StringBuffer();
     _writeSelectionToBuffer(buffer, selection);
+    // Expectation descriptions are always written with literal newlines as '\n'
+    // so on Windows we will need to update the expectation to '\r\n' before
+    // comparing.
+    expect(
+      expected,
+      isNot(contains(r'\r')),
+      reason:
+          r'Expectations should always be written with literal '
+          "'\n' to indicate newlines regardless of platform",
+    );
+    if (Platform.isWindows) {
+      expected = expected.replaceAll(r'\n', r'\r\n');
+    }
+
     _assertTextExpectation(buffer.toString(), expected);
   }
 
@@ -1423,7 +1439,7 @@ nodesInRange
   }
 
   Future<_CodeSelection> _computeSelection(String annotatedCode) async {
-    var testCode = TestCode.parse(annotatedCode);
+    var testCode = TestCode.parse(normalizeSource(annotatedCode));
     expect(testCode.positions, isEmpty);
     var range = testCode.range.sourceRange;