v0(),
        getMap().putIfAbsent(k0(), v3()));
    expectUnchanged();
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  public void testPutIfAbsent_unsupportedAbsent() {
    assertThrows(UnsupportedOperationException.class, () -> putIfAbsent(e3()));
    expectUnchanged();
    expectMissing(e3());
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)

          collection.remove(null));
    } catch (NullPointerException tolerated) {
    }
    expectUnchanged();
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_QUERIES})
  public void testRemove_nullAllowed() {
    assertFalse("remove(null) should return false", collection.remove(null));
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)

        collection.removeAll(MinimalCollection.of()));
    expectUnchanged();
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAll_nonePresent() {
    assertFalse(
        "removeAll(disjointCollection) should return false",
        collection.removeAll(MinimalCollection.of(e3())));
    expectUnchanged();
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)

    } catch (ClassCastException tolerated) { // for ClassToInstanceMap
      expectUnchanged();
    }
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testReplace_supportedPresentNoChange() {
    assertEquals(v0(), getMap().replace(k0(), v0()));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testReplace_supportedAbsent() {

        v0(),
        getMap()
            .computeIfAbsent(
                k0(),
                k -> {
                  throw new AssertionFailedError();
                }));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testComputeIfAbsent_functionReturnsNullNotInserted() {
    assertNull(
        "computeIfAbsent(absent, returnsNull) should return null",
        getMap()

        v0(),
        getMap().putIfAbsent(k0(), v3()));
    expectUnchanged();
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  public void testPutIfAbsent_unsupportedAbsent() {
    assertThrows(UnsupportedOperationException.class, () -> putIfAbsent(e3()));
    expectUnchanged();
    expectMissing(e3());
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)

        () -> getList().addAll(0, MinimalCollection.of(e0(), e3())));
    expectUnchanged();
    expectMissing(e3());
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  public void testAddAllAtIndex_supportedNothing() {
    assertFalse("addAll(n, nothing) should return false", getList().addAll(0, emptyCollection()));
    expectUnchanged();
  }

  @ListFeature.Require(absent = SUPPORTS_ADD_WITH_INDEX)

        v0(),
        getMap().putIfAbsent(k0(), v3()));
    expectUnchanged();
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  public void testPutIfAbsent_unsupportedAbsent() {
    assertThrows(UnsupportedOperationException.class, () -> getMap().putIfAbsent(k3(), v3()));
    expectUnchanged();
    expectMissing(e3());
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)

        collection.removeAll(MinimalCollection.of()));
    expectUnchanged();
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAll_nonePresent() {
    assertFalse(
        "removeAll(disjointCollection) should return false",
        collection.removeAll(MinimalCollection.of(e3())));
    expectUnchanged();
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)

  public void testElement_empty() {
    assertThrows(NoSuchElementException.class, () -> getQueue().element());
    expectUnchanged();
  }

  @CollectionSize.Require(ONE)
  public void testElement_size1() {
    assertEquals("size1Queue.element() should return first element", e0(), getQueue().element());
    expectUnchanged();
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  @CollectionSize.Require(SEVERAL)