}
  }

  @Test fun ofMapRejectsNullCharInValue() {
    assertFailsWith<IllegalArgumentException> {
      mapOf("User-Agent" to "Square\u0000OkHttp").toHeaders()
    }
  }

  @Test fun builderRejectsUnicodeInHeaderName() {
    assertFailsWith<IllegalArgumentException> {
      Headers.Builder().add("héader1", "value1")
    }.also { expected ->
      assertThat(expected.message)