Use ansi color in the dartanalyzer cli output.

pkg/analyzer_cli/test/driver_test.dart

Index: pkg/analyzer_cli/test/driver_test.dart
diff --git a/pkg/analyzer_cli/test/driver_test.dart b/pkg/analyzer_cli/test/driver_test.dart
index 30cc93ac16f2f66587ac8c0748547e2bb3841231..e58c0e92c713a6c1ee357bd4ad5400e3947c53f8 100644
--- a/pkg/analyzer_cli/test/driver_test.dart
+++ b/pkg/analyzer_cli/test/driver_test.dart
@@ -14,6 +14,7 @@ import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/services/lint.dart';
+import 'package:analyzer_cli/src/ansi.dart' as ansi;
 import 'package:analyzer_cli/src/driver.dart';
 import 'package:analyzer_cli/src/options.dart';
 import 'package:cli_util/cli_util.dart' show getSdkDir;
@@ -30,6 +31,7 @@ main() {
 
   /// Base setup.
   _setUp() {
+    ansi.runningTests = true;
     savedOutSink = outSink;
     savedErrorSink = errorSink;
     savedExitHandler = exitHandler;
@@ -45,6 +47,7 @@ main() {
     errorSink = savedErrorSink;
     exitCode = savedExitCode;
     exitHandler = savedExitHandler;
+    ansi.runningTests = false;
   }
 
   setUp(() => _setUp());
@@ -177,7 +180,7 @@ main() {
           test('generates lints', () async {
             await runLinter();
             expect(outSink.toString(),
-                contains('[lint] Name types using UpperCamelCase'));
+                contains('lint • Name types using UpperCamelCase'));

[Brian Wilkerson, 2017/03/23 17:09:51]

Will this work on Windows? Perhaps we should expect the error severity and
message separately.

[devoncarew, 2017/03/25 22:33:17]

There is some checking for 'ansi.runningTests' in order to normalize output a 
bit when testing, so should still pass on windows. I think it does make sense to
split the two checks however, so will do that.

           });
         });
 
@@ -203,7 +206,7 @@ main() {
           test('generates lints', () async {
             await runLinter();
             expect(outSink.toString(),
-                contains('[lint] Name types using UpperCamelCase'));
+                contains('lint • Name types using UpperCamelCase'));
           });
         });
 
@@ -289,7 +292,7 @@ linter:
             expect(
                 outSink.toString(),
                 contains(
-                    "[error] This function declares a return type of 'int'"));
+                    "error • This function declares a return type of 'int'"));
             expect(
                 outSink.toString(), contains("1 error and 1 warning found."));
           });
@@ -328,7 +331,7 @@ linter:
                 ErrorSeverity.WARNING);
             // Should not be made fatal by `--fatal-warnings`.
             expect(outSink.toString(),
-                contains("[warning] The function 'baz' isn't defined"));
+                contains("warning • The function 'baz' isn't defined"));
             expect(
                 outSink.toString(), contains("1 error and 1 warning found."));
           });