Server custom error severity support (#24452).

pkg/analysis_server/test/analysis/notification_analysis_options_test.dart

Index: pkg/analysis_server/test/analysis/notification_analysis_options_test.dart
diff --git a/pkg/analysis_server/test/analysis/notification_analysis_options_test.dart b/pkg/analysis_server/test/analysis/notification_analysis_options_test.dart
index 2eed1579a206047f0463be0ef68604b7d99281ab..a24b8117ce670116c6c35cbcc653bb59022d636c 100644
--- a/pkg/analysis_server/test/analysis/notification_analysis_options_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_analysis_options_test.dart
@@ -102,10 +102,10 @@ main() {
     await waitForTasksFinished();
 
     // Verify options file.
-    expect(optionsFileErrors, hasLength(0));
+    expect(optionsFileErrors, isEmpty);
 
     // Verify test file.
-    expect(testFileErrors, hasLength(0));
+    expect(testFileErrors, isEmpty);
   }
 
   test_error_filter_removed() async {
@@ -126,10 +126,10 @@ main() {
     await waitForTasksFinished();
 
     // Verify options file.
-    expect(optionsFileErrors, hasLength(0));
+    expect(optionsFileErrors, isEmpty);
 
     // Verify test file.
-    expect(testFileErrors, hasLength(0));
+    expect(testFileErrors, isEmpty);
 
     addOptionsFile('''
 analyzer:
@@ -141,7 +141,7 @@ analyzer:
     await waitForTasksFinished();
 
     // Verify options file.
-    expect(optionsFileErrors, hasLength(0));
+    expect(optionsFileErrors, isEmpty);
 
     // Verify test file.
     expect(testFileErrors, hasLength(1));