anchor.diff:  
   import 'dart:convert';
   
  -import 'package:matcher/matcher.dart';
  +import "package:expect/expect.dart";
   
   void _testIndentWithNullChar() {
     var encoder = const JsonEncoder.withIndent('\x00');
     var encoded = encoder.convert([[],[[]]]);
  -  expect(encoded, "[\n\x00[],\n\x00[\n\x00\x00[]\n\x00]\n]");
  +  Expect.equals("[\n\x00[],\n\x00[\n\x00\x00[]\n\x00]\n]", encoded);
   }
   
   void main() {
  
positive.code:   var encoder = const JsonEncoder.withIndent('  ');
    var prettyOutput = encoder.convert(object);
  
    expect(prettyOutput, expected);
  
    encoder = const JsonEncoder.withIndent('');
  
  
negative.code:       .map((line) => line.trimLeft())
        .join('\n');
  
    Expect.equals(flatExpected, flatOutput);
  
    var compactOutput = JSON.encode(object);
  
    encoder = const JsonEncoder.withIndent(null);
    Expect.equals(compactOutput, encoder.convert(object));
  
    var prettyDecoded = JSON.decode(prettyOutput);
  
    Expect.equals(compactOutput, JSON.encode(prettyDecoded));
  }
  