verifyHostname(hostname, it)
    }
  }

  /**
   * This is like [toLowerCase] except that it does nothing if this contains any non-ASCII
   * characters. We want to avoid lower casing special chars like U+212A (Kelvin symbol) because
   * they can return ASCII characters that match real hostnames.
   */
  private fun String.asciiToLowercase(): String {
    return when {
      isAscii() -> lowercase(Locale.US) // This is an ASCII string.

    // These should ideally be false, but we know that hostname is usually already checked by us
    assertThat(verifier.verify("\u212A.com", session)).isFalse()
    // Kelvin character below
    assertThat(verifier.verify("K.com", session)).isFalse()
  }

  @Test fun specialKInCert() {
    // https://github.com/apache/httpcomponents-client/commit/303e435d7949652ea77a6c50df1c548682476b6e

    // Map the single character telephone symbol (℡) to the string "tel".
    assertThat(parse("http://\u2121").host).isEqualTo("tel")

    // Map the Kelvin symbol (K) to the string "k".
    assertThat(parse("http://\u212A").host).isEqualTo("k")
  }

  @Test
  fun quirks() {
    assertThat(parse("http://facebook.com").host).isEqualTo("facebook.com")

<a href="#Interface_types">interface type</a>.
</p>

<p>
Examples of interfaces with core types:
</p>

<pre>
type Celsius float32
type Kelvin  float32

interface{ int }                          // int
interface{ Celsius|Kelvin }               // float32
interface{ ~chan int }                    // chan int
interface{ ~chan int|~chan&lt;- int }        // chan&lt;- int

2129          ; valid                  ;      ; NV8    # 1.1  TURNED GREEK SMALL LETTER IOTA
212A          ; mapped                 ; 006B          # 1.1  KELVIN SIGN
212B          ; mapped                 ; 00E5          # 1.1  ANGSTROM SIGN
212C          ; mapped                 ; 0062          # 1.1  SCRIPT CAPITAL B