boolean suppressGetSupertype() default false;
  }

  private @Nullable Method method = null;

  /** Call this in a {@link TestSubtype} public method asserting subtype relationship. */
  final <T> T isSubtype(T sub) {
    Type returnType = method.getGenericReturnType();
    Type paramType = getOnlyParameterType();
    TestSubtype spec = method.getAnnotation(TestSubtype.class);

          }
        }
      }
      return this;
    }

    /**
     * Tests {@link Object#equals} and {@link Object#hashCode} against the return values of the
     * static methods, by asserting that when equal parameters are passed to the same static method,
     * the return value should also be equal; and vice versa.
     *
     * <p>Test fails if default value cannot be determined for a constructor or factory method

import java.util.List;
import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A series of tests that support asserting that collections cannot be modified, either through
 * direct or indirect means.
 *
 * @author Robert Konigsberg
 */
@GwtCompatible
@NullMarked
public class UnmodifiableCollectionTests {

          }
        }
      }
      return this;
    }

    /**
     * Tests {@link Object#equals} and {@link Object#hashCode} against the return values of the
     * static methods, by asserting that when equal parameters are passed to the same static method,
     * the return value should also be equal; and vice versa.
     *
     * <p>Test fails if default value cannot be determined for a constructor or factory method

    waiter.join();
    future.set(null);
    poller.join();
  }

  public void testToString_allUnique() throws Exception {
    // Two futures should not have the same toString, to avoid people asserting on it
    assertThat(SettableFuture.create().toString()).isNotEqualTo(SettableFuture.create().toString());
  }

  public void testToString_oom() throws Exception {

    waiter.join();
    future.set(null);
    poller.join();
  }

  public void testToString_allUnique() throws Exception {
    // Two futures should not have the same toString, to avoid people asserting on it
    assertThat(SettableFuture.create().toString()).isNotEqualTo(SettableFuture.create().toString());
  }

  public void testToString_oom() throws Exception {