new Builder<String, Integer>()
            .put("one", 1)
            .put("one", 1); // throwing on this line would be even better

    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> builder.build());
    assertThat(expected).hasMessageThat().contains("one");
  }

  public void testOf() {
    assertMapEquals(ImmutableBiMap.of("one", 1), "one", 1);

          ToOptionalState::getOptional,
          Collector.Characteristics.UNORDERED);

  /**
   * A collector that converts a stream of zero or one elements to an {@code Optional}.
   *
   * @throws IllegalArgumentException if the stream consists of two or more elements.
   * @throws NullPointerException if any element in the stream is {@code null}.
   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be

            throws ProjectBuilderException, IllegalArgumentException {
        InternalSession session = InternalSession.from(request.getSession());
        return session.request(request, this::doBuild);
    }

    protected ProjectBuilderResult doBuild(ProjectBuilderRequest request)
            throws ProjectBuilderException, IllegalArgumentException {

      "pass" -> password = value
      "h" -> host = value
      "port" -> port = value
      "p" -> path = value
      "q" -> query = value
      "f" -> fragment = value
      else -> throw IllegalArgumentException("unexpected attribute: $value")
    }
  }

  override fun toString(): String = format("Parsing: <%s> against <%s>", input!!, base!!)

  companion object {

  }

  public void testTrailingHighSurrogate() {
    String test = "abc" + Character.MIN_HIGH_SURROGATE;
    assertThrows(IllegalArgumentException.class, () -> escapeAsString(NOP_ESCAPER, test));
    assertThrows(IllegalArgumentException.class, () -> escapeAsString(SIMPLE_ESCAPER, test));
  }

  @SuppressWarnings("nullness") // test of bogus call
  public void testNullInput() {

     * silently {@link #addNode(Object) add} each missing endpoint to the graph.
     *
     * @return this {@code Builder} object
     * @throws IllegalArgumentException if the introduction of the edge would violate {@link
     *     #allowsSelfLoops()}
     * @throws IllegalArgumentException if the endpoints are unordered and the graph is directed
     */
    @CanIgnoreReturnValue
    public Builder<N> putEdge(EndpointPair<N> endpoints) {

  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testCreateWithDuplicates_nullDuplicatesRejected() {
    E[] array = createArrayWithNullElement();
    array[0] = null;
    assertThrows(
        IllegalArgumentException.class, () -> collection = getSubjectGenerator().create(array));
  }

  @CollectionFeature.Require(REJECTS_DUPLICATES_AT_CREATION)
  @CollectionSize.Require(absent = {ZERO, ONE})

  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testCreateWithDuplicates_nullDuplicatesRejected() {
    E[] array = createArrayWithNullElement();
    array[0] = null;
    assertThrows(
        IllegalArgumentException.class, () -> collection = getSubjectGenerator().create(array));
  }

  @CollectionFeature.Require(REJECTS_DUPLICATES_AT_CREATION)
  @CollectionSize.Require(absent = {ZERO, ONE})

        } else if (nonce.length == 16) {
            // For GCM cipher, use full 16-byte nonce
            System.arraycopy(nonce, 0, this.nonce, 0, 16);
        } else {
            throw new IllegalArgumentException("Nonce must be 12 bytes (CCM) or 16 bytes (GCM)");
        }
        this.originalMessageSize = originalMessageSize;
        this.flags = flags;
        this.sessionId = sessionId;
    }

    /**

  }

  public void testFixedLengthSplitZeroChunkLen() {
    assertThrows(IllegalArgumentException.class, () -> Splitter.fixedLength(0));
  }

  public void testFixedLengthSplitNegativeChunkLen() {
    assertThrows(IllegalArgumentException.class, () -> Splitter.fixedLength(-1));
  }

  public void testLimitLarge() {
    String simple = "abcd";