namesAndValues["User-Agent"] = "OkHttp"
    val headers = namesAndValues.toHeaders()
    namesAndValues["User-Agent"] = "Chrome"
    assertThat(headers.value(0)).isEqualTo("OkHttp")
  }

  @Test fun ofMapRejectsNullCharInName() {
    assertFailsWith<IllegalArgumentException> {
      mapOf("User-\u0000Agent" to "OkHttp").toHeaders()
    }
  }

  @Test fun ofMapRejectsNullCharInValue() {