public String property(String key) {
    return properties.get(key);
  }
@Test
  public void encryption_ok() {
    ImmutableMap<String, String> map = ImmutableMap.<String, String>builder()
      .put("prop-1", "{b64}Zm9v")
      .build();
    ScannerProperties underTest = new ScannerProperties(map);

    assertThat(underTest.property("prop-1")).isEqualTo("foo");
  }