cleanup/organize/improve completion tests

pkg/analysis_server/test/services/completion/completion_test_util.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.services.completion.util;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart' as protocol show Element,
     ElementKind;
@@ skipping 35 matching lines @@
     int nextOffset = content.indexOf('^', completionOffset + 1);
     expect(nextOffset, equals(-1), reason: 'too many ^');
     content = content.substring(0, completionOffset) +
         content.substring(completionOffset + 1);
     testSource = addSource(testFile, content);
     request =
         new DartCompletionRequest(context, searchEngine, testSource, completionOffset);
   }
 
   void assertNotSuggested(String completion) {
-    if (request.suggestions.any((cs) => cs.completion == completion)) {
-      _failWithNodeInfo('did not expect completion: $completion');
+    CompletionSuggestion suggestion = request.suggestions.firstWhere(
+        (cs) => cs.completion == completion,
+        orElse: () => null);
+    if (suggestion != null) {
+      _failedCompletion(
+          'did not expect completion: $completion\n  $suggestion');
     }
   }
 
   CompletionSuggestion assertSuggest(CompletionSuggestionKind kind,
       String completion, [CompletionRelevance relevance = CompletionRelevance.DEFAULT,
       bool isDeprecated = false, bool isPotential = false]) {
     CompletionSuggestion cs;
     request.suggestions.forEach((s) {
       if (s.completion == completion) {
         if (cs == null) {
           cs = s;
         } else {
-          List<CompletionSuggestion> completions =
-              request.suggestions.where((s) => s.completion == completion).toList();
-          _failWithNodeInfo(
-              'expected exactly one $completion but found > 1\n$completions');
+          _failedCompletion(
+              'expected exactly one $completion',
+              request.suggestions.where((s) => s.completion == completion));
         }
       }
     });
     if (cs == null) {
-      List<CompletionSuggestion> completions =
-          request.suggestions.map((s) => s.completion).toList();
-      _failWithNodeInfo('expected "$completion" but found\n $completions');
+      _failedCompletion('expected $completion', request.suggestions);
     }
     expect(cs.kind, equals(kind));
     expect(cs.relevance, equals(relevance));
     expect(cs.selectionOffset, equals(completion.length));
     expect(cs.selectionLength, equals(0));
     expect(cs.isDeprecated, equals(isDeprecated));
     expect(cs.isPotential, equals(isPotential));
     return cs;
   }
 
@@ skipping 192 matching lines @@
     return computer.computeFull(request);
   }
 
   @override
   void setUp() {
     super.setUp();
     index = createLocalMemoryIndex();
     searchEngine = new SearchEngineImpl(index);
   }
 
-  void _failWithNodeInfo(String message) {
+  void _failedCompletion(String message,
+      [Iterable<CompletionSuggestion> completions]) {
     StringBuffer sb = new StringBuffer(message);
+    if (completions != null) {
+      sb.write('\n  found');
+      completions.toList()
+          ..sort((CompletionSuggestion s1, CompletionSuggestion s2) {
+            String c1 = s1.completion.toLowerCase();
+            String c2 = s2.completion.toLowerCase();
+            return c1.compareTo(c2);
+          })
+          ..forEach((CompletionSuggestion suggestion) {
+            sb.write('\n    ${suggestion.completion} -> $suggestion');
+          });
+    }
     if (completionNode != null) {
       sb.write('\n  in');
       AstNode node = completionNode;
       while (node != null) {
         sb.write('\n    ${node.runtimeType}');
         node = node.parent;
       }
     }
     fail(sb.toString());
   }
 }