Switch analysis_server to use 'package:test'.

pkg/analysis_server/test/integration/analysis/occurrences_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 library test.integration.analysis.occurrences;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
-import 'package:unittest/unittest.dart';
 
 import '../../utils.dart';
 import '../integration_tests.dart';
 
 main() {
   initializeTestEnvironment();
-  defineReflectiveTests(Test);
+  defineReflectiveSuite(() {
+    defineReflectiveTests(Test);
+  });
 }
 
 @reflectiveTest
 class Test extends AbstractAnalysisServerIntegrationTest {
   test_occurrences() {
     String pathname = sourcePath('test.dart');
     String text = r'''
 main() {
   int sum = 0;
   for (int i = 0; i < 10; i++) {
@@ skipping 18 matching lines @@
       expect(currentAnalysisErrors[pathname], isEmpty);
       Set<int> findOffsets(String elementName) {
         for (Occurrences occurrence in occurrences) {
           if (occurrence.element.name == elementName) {
             return occurrence.offsets.toSet();
           }
         }
         fail('No element found matching $elementName');
         return null;
       }
+
       void check(String elementName, Iterable<String> expectedOccurrences) {
         Set<int> expectedOffsets = expectedOccurrences
             .map((String substring) => text.indexOf(substring))
             .toSet();
         Set<int> foundOffsets = findOffsets(elementName);
         expect(foundOffsets, equals(expectedOffsets));
       }
+
       check('i', ['i = 0', 'i < 10', 'i++', 'i;']);
       check('j', ['j = 0', 'j < i', 'j++', 'j;']);
       check('sum', ['sum = 0', 'sum +=', 'sum)']);
     });
   }
 }