}

  public void testOpen_invalid() {
    assertThrows(IllegalArgumentException.class, () -> Range.open(4, 3));
    assertThrows(IllegalArgumentException.class, () -> Range.open(3, 3));
  }

  public void testClosed() {
    Range<Integer> range = Range.closed(5, 7);
    checkContains(range);
    assertTrue(range.hasLowerBound());
    assertEquals(5, (int) range.lowerEndpoint());
    assertEquals(CLOSED, range.lowerBoundType());

  }

  public void testOpen_invalid() {
    assertThrows(IllegalArgumentException.class, () -> Range.open(4, 3));
    assertThrows(IllegalArgumentException.class, () -> Range.open(3, 3));
  }

  public void testClosed() {
    Range<Integer> range = Range.closed(5, 7);
    checkContains(range);
    assertTrue(range.hasLowerBound());
    assertEquals(5, (int) range.lowerEndpoint());
    assertEquals(CLOSED, range.lowerBoundType());

		}
		testReadFrom struct { // ReadFrom(testFile{ops}) == (wantCnt, wantErr)
			ops     fileOps
			wantCnt int64
			wantErr error
		}
		testClose struct { // Close() == wantErr
			wantErr error
		}
		testFnc any // testHeader | testWrite | testReadFrom | testClose
	)

	vectors := []struct {
		file     string // Optional filename of expected output
		obscured bool   // Whether file is obscured
		tests    []testFnc