Fix an issue with duplicate reported analysis errors.

pkg/analyzer_cli/test/reporter_test.dart

 // Copyright (c) 2015, 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 analyzer_cli.test.formatter;
 
 import 'package:analyzer/analyzer.dart';
+import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer_cli/src/ansi.dart' as ansi;
 import 'package:analyzer_cli/src/error_formatter.dart';
 import 'package:test/test.dart' hide ErrorFormatter;
 import 'package:typed_mock/typed_mock.dart';
 
 import 'mocks.dart';
 
 main() {
   group('reporter', () {
-    var out = new StringBuffer();
-    var stats = new AnalysisStats();
+    StringBuffer out;
+    AnalysisStats stats;
+    MockCommandLineOptions options;
+    ErrorFormatter reporter;
 
     setUp(() {
       ansi.runningTests = true;
-      stats.init();
+
+      out = new StringBuffer();
+      stats = new AnalysisStats();
+
+      options = new MockCommandLineOptions();
+      when(options.enableTypeChecks).thenReturn(false);
+      when(options.hintsAreFatal).thenReturn(false);
+      when(options.machineFormat).thenReturn(false);
+      when(options.verbose).thenReturn(false);
+      when(options.color).thenReturn(false);
+
+      reporter = new HumanErrorFormatter(out, options, stats);
     });
 
     tearDown(() {
-      out.clear();
       ansi.runningTests = false;
     });
 
-    // Options
-    var options = new MockCommandLineOptions();
-    when(options.enableTypeChecks).thenReturn(false);
-    when(options.hintsAreFatal).thenReturn(false);
-    when(options.machineFormat).thenReturn(false);
-    when(options.verbose).thenReturn(false);
-    when(options.color).thenReturn(false);
-
-    var reporter = new ErrorFormatter(out, options, stats);
-
     test('error', () {
-      var error = mockError(ErrorType.SYNTACTIC_ERROR, ErrorSeverity.ERROR);
+      AnalysisErrorInfo error =
+          mockError(ErrorType.SYNTACTIC_ERROR, ErrorSeverity.ERROR);
       reporter.formatErrors([error]);
+      reporter.flush();
 
       expect(out.toString().trim(),
           'error • MSG at /foo/bar/baz.dart:3:3 • mock_code');
     });
 
     test('hint', () {
-      var error = mockError(ErrorType.HINT, ErrorSeverity.INFO);
+      AnalysisErrorInfo error = mockError(ErrorType.HINT, ErrorSeverity.INFO);
       reporter.formatErrors([error]);
+      reporter.flush();
 
       expect(out.toString().trim(),
           'hint • MSG at /foo/bar/baz.dart:3:3 • mock_code');
     });
 
     test('stats', () {
-      var error = mockError(ErrorType.HINT, ErrorSeverity.INFO);
+      AnalysisErrorInfo error = mockError(ErrorType.HINT, ErrorSeverity.INFO);
       reporter.formatErrors([error]);
+      reporter.flush();
       stats.print(out);
       expect(
           out.toString().trim(),
           'hint • MSG at /foo/bar/baz.dart:3:3 • mock_code\n'
           '1 hint found.');
     });
   });
 }
 
 MockAnalysisErrorInfo mockError(ErrorType type, ErrorSeverity severity) {
   // ErrorInfo
   var info = new MockAnalysisErrorInfo();
   var error = new MockAnalysisError();
   var lineInfo = new MockLineInfo();
   var location = new MockLineInfo_Location();
   when(location.columnNumber).thenReturn(3);
   when(location.lineNumber).thenReturn(3);
   when(lineInfo.getLocation(anyObject)).thenReturn(location);
   when(info.lineInfo).thenReturn(lineInfo);
 
   // Details
   var code = new MockErrorCode();
   when(code.type).thenReturn(type);
   when(code.errorSeverity).thenReturn(severity);
   when(code.name).thenReturn('mock_code');
   when(error.errorCode).thenReturn(code);
   when(error.message).thenReturn('MSG');
+  when(error.offset).thenReturn(20);
   var source = new MockSource();
   when(source.fullName).thenReturn('/foo/bar/baz.dart');
   when(error.source).thenReturn(source);
   when(info.errors).thenReturn([error]);
 
   return info;
 }