}
		} else {
			os.Unsetenv(test.key)
		}

		t.Run(test.name, func(t *testing.T) {
			t.Setenv(test.key, test.newValue)
			if os.Getenv(test.key) != test.newValue {
				t.Fatalf("unexpected value after t.Setenv: got %s, want %s", os.Getenv(test.key), test.newValue)
			}
		})

		got, exists := os.LookupEnv(test.key)
		if got != test.initialValue {

   * iterator tests.
   *
   * @return the new container instance
   * @param newValue the new container instance
   */
  @CanIgnoreReturnValue
  protected C resetContainer(C newValue) {
    container = newValue;
    return container;
  }

  /**
   * @see #expectContents(java.util.Collection)
   * @param elements expected contents of {@link #container}

     *
     * @param key the key under which to store the session data, must not be {@code null}
     * @param oldValue the expected data currently associated with the key, may be {@code null}
     * @param newValue the data to associate with the key, may be {@code null} to remove the mapping
     * @return {@code true} if the key mapping was successfully updated from the old value to the new value,

           * nullness checker.
           */
          K key = keyFunction.apply(t);
          V newValue = valueFunction.apply(t);
          accum.put(
              checkNotNull(key, "Null key for input %s", t),
              checkNotNull(newValue, "Null value for input %s", t));
        },
        EnumMapAccumulator::combine,
        EnumMapAccumulator::toImmutableMap,

           * nullness checker.
           */
          K key = keyFunction.apply(t);
          V newValue = valueFunction.apply(t);
          accum.put(
              checkNotNull(key, "Null key for input %s", t),
              checkNotNull(newValue, "Null value for input %s", t));
        },
        EnumMapAccumulator::combine,
        EnumMapAccumulator::toImmutableMap,

    @Override
    @CheckForNull
    V getValue(int index) {
      return at(index, columnIndex);
    }

    @Override
    @CheckForNull
    V setValue(int index, @CheckForNull V newValue) {
      return set(index, columnIndex, newValue);
    }
  }

  /**
   * Returns an immutable set of the valid column keys, including those that are associated with
   * null values only.
   *

    @Override
    @CheckForNull
    V getValue(int index) {
      return at(index, columnIndex);
    }

    @Override
    @CheckForNull
    V setValue(int index, @CheckForNull V newValue) {
      return set(index, columnIndex, newValue);
    }
  }

  /**
   * Returns an immutable set of the valid column keys, including those that are associated with
   * null values only.
   *

      }
    }

    @Override
    void putThread(Waiter waiter, Thread newValue) {
      UNSAFE.putObject(waiter, WAITER_THREAD_OFFSET, newValue);
    }

    @Override
    void putNext(Waiter waiter, @CheckForNull Waiter newValue) {
      UNSAFE.putObject(waiter, WAITER_NEXT_OFFSET, newValue);
    }

    /** Performs a CAS operation on the {@link #waiters} field. */
    @Override

      }
    }

    @Override
    void putThread(Waiter waiter, Thread newValue) {
      UNSAFE.putObject(waiter, WAITER_THREAD_OFFSET, newValue);
    }

    @Override
    void putNext(Waiter waiter, @CheckForNull Waiter newValue) {
      UNSAFE.putObject(waiter, WAITER_NEXT_OFFSET, newValue);
    }

    /** Performs a CAS operation on the {@link #waiters} field. */
    @Override

    Integer oldValue = map.putInstance(Integer.class, Integer.valueOf(7));
    assertEquals(5, (int) oldValue);

    Integer newValue = map.getInstance(Integer.class);
    assertEquals(7, (int) newValue);
    assertEquals(7, (int) map.getInstance(TypeToken.of(Integer.class)));

    // Won't compile: map.putInstance(Double.class, new Long(42));
  }

  public void testNull() {