anchor.diff:     * given tolerance. If no tolerance is given, tolerance is assumed to be the
      * value 4 significant digits smaller than the value given for expected.
      */
  -  @deprecated
     static void approxEquals(num expected,
                              num actual,
                              [num tolerance = null,
  
positive.code: library Expect;
  
  /**
   * This class is *deprecated*.
   *
   * Expect is used for tests that do not want to make use of the
   * Dart unit test library - for example, the core language tests.
   * Third parties are discouraged from using this, and should use
   * the expect() function in the unit test library instead for
   * test assertions.
   */
  @deprecated
  class Expect {
    /**
     * Checks whether the expected and actual values are equal (using `==`).
     */
    @deprecated
    static void equals(var expected, var actual, [String reason = null]) {
      if (expected == actual) return;
      String msg = _getMessage(reason);
  
negative.code:    * the semantics of [Map.containsKey] to determine what "same" means. For
     * each key, checks that the values in both maps are equal using `==`.
     */
    static void mapEquals(Map expected, Map actual, [String reason = null]) {
      String msg = _getMessage(reason);
  
  