anchor.diff:        ..contentEditable = "false";
       textArea.classes.add('code-editor-text-area');
       target.children..add(runBtn)..add(output);
  -    if (options != null) this.options = options;
  +    this.options = options == null ? this.options : options;
       _editor = new CodeMirror.fromTextArea(textArea, options: this.options);
       output
         ..text = "output"
  
positive.code: const String startingCCode = """#include "stdio.h"
  
  int main() {
    printf("Hello, C!\\n");
    return 0;
  }""";
  
  const String startingCPPCode = """#include <iostream>
  
  int main() {
    std::cout << "Hello, C++!" << std::endl;
    return 0;
  }""";
  
  const String startingPython3Code = """print("Hello, Python 3!")""";
  
negative.code:     'autoCloseTags': true,
      'mode': 'clike',
      'matchBrackets': true,
      'indentUnit': 4,
      'extraKeys': {
        'Ctrl-Space': 'autocomplete',
        'Cmd-/': 'toggleComment',
  