essage: "yoffset is not a multiple of 4" },
      { xoffset: 12, yoffset: 12, width: 4, height: 4,
        expectation: gl.NO_ERROR, message: "is valid" },
  ]);

  // Test TexImage validation on level dimensions combinations.
  // When level equals 0, width and height must be a multiple of 4.
  // When level is larger than 0, this constraint doesn't apply.

  let npotExpectation, npotMessage;
  if (contextVersion >= 2) {
    npotExpectation = gl.NO_ERROR;
    npotMessage = "valid";
  } else {
    npotExpec