this.replacementsLength = replacements.length;
    if (safeMax < safeMin) {
      // If the safe range is empty, set the range limits to opposite extremes
      // to ensure the first test of either value will fail.
      safeMax = -1;
      safeMin = Integer.MAX_VALUE;
    }
    this.safeMin = safeMin;
    this.safeMax = safeMax;

    if (safeMax < safeMin) {
      // If the safe range is empty, set the range limits to opposite extremes
      // to ensure the first test of either value will (almost certainly) fail.
      safeMax = Character.MIN_VALUE;
      safeMin = Character.MAX_VALUE;
    }
    this.safeMin = safeMin;
    this.safeMax = safeMax;
  }

  /*

     * safeMax < safeMin} then the safe range is empty.
     *
     * @param safeMin the lowest 'safe' character
     * @param safeMax the highest 'safe' character
     * @return the builder instance
     */
    @CanIgnoreReturnValue
    public Builder setSafeRange(char safeMin, char safeMax) {
      this.safeMin = safeMin;
      this.safeMax = safeMax;
      return this;
    }

    assertEquals("The Quick Brown Fox", escaper.escape("The Quick Brown Fox"));
  }

  public void testBuilderInitialStateNoneUnsafe() {
    // No characters are unsafe by default (safeMin == 0, safeMax == 0xFFFF).
    Escaper escaper = Escapers.builder().setUnsafeReplacement("X").build();
    assertEquals("\0\uFFFF", escaper.escape("\0\uFFFF"));
  }

  public void testBuilderRetainsState() {

    assertEquals("The Quick Brown Fox", escaper.escape("The Quick Brown Fox"));
  }

  public void testBuilderInitialStateNoneUnsafe() {
    // No characters are unsafe by default (safeMin == 0, safeMax == 0xFFFF).
    Escaper escaper = Escapers.builder().setUnsafeReplacement("X").build();
    assertEquals("\0\uFFFF", escaper.escape("\0\uFFFF"));
  }

  public void testBuilderRetainsState() {