alid");
    wtu.glErrorShouldBe(gl, gl.NO_ERROR);
    shouldBeUndefined('gl.drawElements(gl.TRIANGLES, 3, gl.UNSIGNED_INT, 0)');
    wtu.glErrorShouldBe(gl, gl.NO_ERROR);

    debug("Test with enabled attribute that does not belong to current program");

    gl.disableVertexAttribArray(normalLoc);
    var extraLoc = Math.max(vertexLoc, normalLoc) + 1;
    gl.enableVertexAttribArray(extraLoc);
    debug("Enable an extra attribute with null");
    wtu.glErrorShouldBe(gl, gl.NO_ERROR);
    shouldBeUndefined('g