anchor.diff:  @reflectiveTest
   class CompletionDomainHandlerListTokenDetailsTest
       extends AbstractCompletionDomainTest {
  +  String testFileUri;
  +
     void expectTokens(String content, List<TokenDetails> expectedTokens) async {
       newFile(testFile, content: content);
       Request request =
  
positive.code:       token('mixin', null, null),
        token('D', 'dart:core;Type', ['declaration']),
        token('on', null, null),
        token('A', 'dart:core;Type<file:///project/bin/test.dart;A>',
            ['reference']),
        token('implements', null, null),
        token('B', 'dart:core;Type<file:///project/bin/test.dart;B>',
            ['reference']),
        token('{', null, null),
        token('}', null, null),
      ]);
  
negative.code:       token('class', null, null),
        token('B', 'dart:core;Type', ['declaration']),
        token('extends', null, null),
        token('A', 'dart:core;Type<$testFileUri;A>', ['reference']),
        token('{', null, null),
        token('}', null, null),
        token('class', null, null),
        token('C', 'dart:core;Type', ['declaration']),
        token('implements', null, null),
        token('B', 'dart:core;Type<$testFileUri;B>', ['reference']),
        token('{', null, null),
        token('}', null, null),
        token('class', null, null),
        token('D', 'dart:core;Type', ['declaration']),
        token('with', null, null),
        token('C', 'dart:core;Type<$testFileUri;C>', ['reference']),
        token('{', null, null),
        token('}', null, null),
      ]);
  