assertThat(expected).hasMessageThat().contains("connected");

    // adjacent below
    assertEquals(Range.closedOpen(4, 4), range.intersection(Range.closedOpen(2, 4)));

    // overlap below
    assertEquals(Range.closed(4, 6), range.intersection(Range.closed(2, 6)));

    // enclosed with same start
    assertEquals(Range.closed(4, 6), range.intersection(Range.closed(4, 6)));

* Missing null checks may cause NullPointerException
* Bridging with Kotlin code is polluted with platform types
* Some public APIs have incorrect nullability annotations (both overly restrictive and overly permissive)

While there are competing ways to represent absence (`Optional`, "Null Object" pattern, method overloads),
it is unlikely that we'll be able to remove `null` entirely.

   * Overlapping ranges and empty ranges are forbidden, though adjacent ranges are permitted and
   * will be merged.
   *
   * @throws IllegalArgumentException if any ranges overlap or are empty
   * @since 21.0
   */
  public static <C extends Comparable<?>> ImmutableRangeSet<C> copyOf(Iterable<Range<C>> ranges) {
    return new ImmutableRangeSet.Builder<C>().addAll(ranges).build();
  }

    assertThat(expected).hasMessageThat().contains("connected");

    // adjacent below
    assertEquals(Range.closedOpen(4, 4), range.intersection(Range.closedOpen(2, 4)));

    // overlap below
    assertEquals(Range.closed(4, 6), range.intersection(Range.closed(2, 6)));

    // enclosed with same start
    assertEquals(Range.closed(4, 6), range.intersection(Range.closed(4, 6)));

        ComponentUtil.setFessConfig(null);
        super.tearDown(testInfo);
    }

    // ==========================================================================
    // addMapping overload delegation
    // ==========================================================================

    @Test
    public void test_addMapping_threeArgDelegatesToFourArgWithLoadBulkDataTrue() {

Also, the best approach was to use already existing standards.

So, before even starting to code **FastAPI**, I spent several months studying the specs for OpenAPI, JSON Schema, OAuth2, etc. Understanding their relationship, overlap, and differences.

## Design { #design }

Then I spent some time designing the developer "API" I wanted to have as a user (as a developer using FastAPI).

    // ambiguous without the cast to Object because the boxed predicate prevents any overload from
    // being selected in phase 1
    checkState(boxedBoolean, "", (Object) boxedLong);

    // ternaries introduce their own problems. because of the ternary (which requires a boxing
    // operation) no overload can be selected in phase 1.  and in phase 2 it is ambiguous since it

    // ambiguous without the cast to Object because the boxed predicate prevents any overload from
    // being selected in phase 1
    checkState(boxedBoolean, "", (Object) boxedLong);

    // ternaries introduce their own problems. because of the ternary (which requires a boxing
    // operation) no overload can be selected in phase 1.  and in phase 2 it is ambiguous since it

      return delegate;
    }

    @Override
    public int size() {
      return delegate.size() + delta;
    }
  }

  @SuppressWarnings("JoinIterableIterator") // explicitly testing iterator overload, too
  public void testNoSpecialNullBehavior() {
    checkNoOutput(J, iterable);
    checkResult(J, iterable1, "1");
    checkResult(J, iterable12, "1-2");
    checkResult(J, iterable123, "1-2-3");

import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Unit test for {@link FakeTicker}.
 *
 * @author Jige Yu
 */
@GwtCompatible
// We also want to test the TimeUnit overload (especially under GWT, where it's the only option).
@SuppressWarnings("SetAutoIncrementStep_Nanos")
@NullUnmarked
public class FakeTickerTest extends TestCase {

  @GwtIncompatible // NullPointerTester