assertThrows(IllegalArgumentException.class, () -> Ints.ensureCapacity(ARRAY1, -1, 1));
    assertThrows(IllegalArgumentException.class, () -> Ints.ensureCapacity(ARRAY1, 1, -1));
  }

  public void testJoin() {
    assertThat(Ints.join(",", EMPTY)).isEmpty();
    assertThat(Ints.join(",", ARRAY1)).isEqualTo("1");
    assertThat(Ints.join(",", (int) 1, (int) 2)).isEqualTo("1,2");

    assertThrows(IllegalArgumentException.class, () -> Doubles.ensureCapacity(ARRAY1, 1, -1));
  }

  @GwtIncompatible // Double.toString returns different value in GWT.
  public void testJoin() {
    assertThat(Doubles.join(",", EMPTY)).isEmpty();
    assertThat(Doubles.join(",", ARRAY1)).isEqualTo("1.0");
    assertThat(Doubles.join(",", (double) 1, (double) 2)).isEqualTo("1.0,2.0");

    assertThrows(IllegalArgumentException.class, () -> Floats.ensureCapacity(ARRAY1, 1, -1));
  }

  @GwtIncompatible // Float.toString returns different value in GWT.
  public void testJoin() {
    assertThat(Floats.join(",", EMPTY)).isEmpty();
    assertThat(Floats.join(",", ARRAY1)).isEqualTo("1.0");
    assertThat(Floats.join(",", (float) 1, (float) 2)).isEqualTo("1.0,2.0");

    assertThrows(IllegalArgumentException.class, () -> Longs.ensureCapacity(ARRAY1, -1, 1));
    assertThrows(IllegalArgumentException.class, () -> Longs.ensureCapacity(ARRAY1, 1, -1));
  }

  public void testJoin() {
    assertThat(Longs.join(",", EMPTY)).isEmpty();
    assertThat(Longs.join(",", ARRAY1)).isEqualTo("1");
    assertThat(Longs.join(",", (long) 1, (long) 2)).isEqualTo("1,2");