checkFromStringCase("google.com:25\t", 1, null, 99, false);
    checkFromStringCase("google.com:0x25 ", 1, null, 99, false);
  }

  public void testFromStringUnparseableNonsense() {
    // Some nonsense that causes parse failures.
    checkFromStringCase("[goo.gl]", 1, null, 99, false);
    checkFromStringCase("[goo.gl]:80", 1, null, 99, false);
    checkFromStringCase("[", 1, null, 99, false);

    checkFromStringCase("google.com:25\t", 1, null, 99, false);
    checkFromStringCase("google.com:0x25 ", 1, null, 99, false);
  }

  public void testFromStringUnparseableNonsense() {
    // Some nonsense that causes parse failures.
    checkFromStringCase("[goo.gl]", 1, null, 99, false);
    checkFromStringCase("[goo.gl]:80", 1, null, 99, false);
    checkFromStringCase("[", 1, null, 99, false);

    .build();
```

Client Authentication
---------------------

The above scenario is representative of most TLS set ups: the client uses certificates to validate
the identity of a server. The converse is also possible. Here we create a server that authenticates
a client and a client that authenticates a server.

```java
// Create the root for client and server to trust. We could also use different roots for each!

     * int.
     */
    checkNonNegative("a", a);
    checkNonNegative("b", b);
    if (a == 0) {
      // 0 % b == 0, so b divides a, but the converse doesn't hold.
      // BigInteger.gcd is consistent with this decision.
      return b;
    } else if (b == 0) {
      return a; // similar logic
    }
    /*