assertTrue(set instanceof SingletonImmutableSet);
    assertEquals(Lists.newArrayList("a"), Lists.newArrayList(set));
  }

  public void testCreation_oneDuplicate() {
    // now we'll get the varargs overload
    ImmutableSet<String> set =
        ImmutableSet.of("a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "a");
    assertEquals(

    assertTrue("addAll(n, containsNull) should return true", getList().addAll(0, containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded(0, (E) null);
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)

    assertTrue("addAll(n, containsNull) should return true", getList().addAll(0, containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded(0, (E) null);
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)

    assertFalse(delegate.isVarArgs());
  }

  public void testPrivateFinalInstanceMethod_isOverridable() throws Exception {
    Invokable<?, ?> delegate = Prepender.method("privateFinalMethod");
    assertTrue(delegate.isPrivate());
    assertTrue(delegate.isFinal());
    assertFalse(delegate.isOverridable());
    assertFalse(delegate.isVarArgs());
  }

    assertFalse(delegate.isVarArgs());
  }

  public void testPrivateFinalInstanceMethod_isOverridable() throws Exception {
    Invokable<?, ?> delegate = Prepender.method("privateFinalMethod");
    assertTrue(delegate.isPrivate());
    assertTrue(delegate.isFinal());
    assertFalse(delegate.isOverridable());
    assertFalse(delegate.isVarArgs());
  }

   *
   * <p><b>Note:</b> essentially the only reason to use this method is when you will need to add or
   * remove elements later. Otherwise, for non-null elements use {@link ImmutableList#of()} (for
   * varargs) or {@link ImmutableList#copyOf(Object[])} (for an array) instead. If any elements
   * might be null, or you need support for {@link List#set(int, Object)}, use {@link
   * Arrays#asList}.
   *

    assertTrue("addAll(containsNull) should return true", collection.addAll(containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded((E) null);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)
  public void testAddAll_nullUnsupported() {

    assertEquals("null [5, 6]", Strings.lenientFormat(null, 5, 6));
    assertEquals("null", Strings.lenientFormat("%s", (Object) null));
  }

  @J2ktIncompatible // TODO(b/319404022): Allow passing null array as varargs
  public void testLenientFormat_nullArrayVarargs() {
    assertEquals("(Object[])null", Strings.lenientFormat("%s", (Object[]) null));
  }

  @GwtIncompatible // GWT reflection includes less data

    assertEquals("null [5, 6]", Strings.lenientFormat(null, 5, 6));
    assertEquals("null", Strings.lenientFormat("%s", (Object) null));
  }

  @J2ktIncompatible // TODO(b/319404022): Allow passing null array as varargs
  public void testLenientFormat_nullArrayVarargs() {
    assertEquals("(Object[])null", Strings.lenientFormat("%s", (Object[]) null));
  }

  @GwtIncompatible // GWT reflection includes less data

   * throws a {@link NullPointerException}.
   *
   * <p>To find the first non-null element in an iterable, use {@code Iterables.find(iterable,
   * Predicates.notNull())}. For varargs, use {@code Iterables.find(Arrays.asList(a, b, c, ...),
   * Predicates.notNull())}, static importing as necessary.
   *
   * <p><b>Note:</b> if {@code first} is represented as an {@link Optional}, this can be