<img src="/img/tutorial/separate-openapi-schemas/image02.png">
</div>

This means that it will **always have a value**, it's just that sometimes the value could be `None` (or `null` in JSON).

That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.

   * could use null, but that messes with our nullness checking, including under J2KT. We could
   * probably work around it by changing how we annotate the J2CL EnumMap, but that's probably more
   * trouble than just using Object.class.)
   *
   * Then we declare the getters for these fields as @GwtIncompatible so that no one can try to use
   * them under J2CL—or, as an unfortunate side effect, under GWT. We do still give the fields

        assertEquals(6, NbtAddress.UNKNOWN_MAC_ADDRESS.length);
    }

    @Test
    void testConstantsAreImmutable() {
        // Ensure constants are properly defined as final
        // This test just verifies the constants exist and are accessible
        String anyHosts = NbtAddress.ANY_HOSTS_NAME;
        String masterBrowser = NbtAddress.MASTER_BROWSER_NAME;
        String smbServer = NbtAddress.SMBSERVER_NAME;

doc/install.html by running godoc --http=:6060 and then visiting http://localhost:6060/doc/install.html. Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file. -- Binary Distribution Notes If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this README). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources...

   * suppression externally, but it's OK because we don't enforce test-size rules there.)
   *
   * We'd just use PackageSanityTests directly, saving us from needing this separate type, but we're
   * currently skipping MediumTests on Android, and we skip them by not making them present at
   * runtime at all. I could just make _this_ test a MediumTest, but then it wouldn't run on

  @Test
  fun testToStringIsClassname() {
    assertThat(Platform().toString()).isEqualTo("Platform")
  }

  @Test
  fun testNotAndroid() {
    platform.assumeNotAndroid()

    // This is tautological so just confirms that it runs.
    assertThat(isAndroid).isEqualTo(false)
  }

    // These contain bytes not in the decodabet.
    assertFailsToDecode(base64(), "A\u007f", "Unrecognized character: 0x7f");
    assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");
    // This sentence just isn't base64() encoded.
    assertFailsToDecode(base64(), "let's not talk of love or chains!");
    // A 4n+1 length string is never legal base64().
    assertFailsToDecode(base64(), "12345", "Invalid input length 5");

                }
            } catch (final Exception ex) {
                final String msg = ex.getMessage();
                final boolean timeout = msg != null && msg.equals("Read timed out");
                /* If just a timeout, try to disconnect gracefully
                 */
                final boolean hard = !timeout;

                if (!timeout && LogStream.level >= 3) {
                    ex.printStackTrace(log);

        #### Utility: compare with alternatives


        There is always *some* alternative to adding a new feature to Guava, even if it's just
        forking Guava yourself.


        We want to see that new features have some significant advantage over the alternatives.
        These advantages can take

    }

    @Test
    void testWriteParameterWordsWireFormat() {
        // This method is empty, just call it for coverage
        assertEquals(0, response.writeParameterWordsWireFormat(new byte[0], 0));
    }

    @Test
    void testWriteBytesWireFormat() {
        // This method is empty, just call it for coverage
        assertEquals(0, response.writeBytesWireFormat(new byte[0], 0));
    }