[Piglit] [PATCH 3/3] etc1: Document expected errors in basic API test

[Chad Versace]

Document why we expect GL_INVALID_OPERATION from gl*TexSubImage2D calls.

Signed-off-by: Chad Versace <chad.versace at linux.intel.com>
---
 .../oes_compressed_etc1_rgb8_texture-basic.c                       | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tests/spec/oes_compressed_etc1_rgb8_texture/oes_compressed_etc1_rgb8_texture-basic.c b/tests/spec/oes_compressed_etc1_rgb8_texture/oes_compressed_etc1_rgb8_texture-basic.c
index dd215d0..028b738 100644
--- a/tests/spec/oes_compressed_etc1_rgb8_texture/oes_compressed_etc1_rgb8_texture-basic.c
+++ b/tests/spec/oes_compressed_etc1_rgb8_texture/oes_compressed_etc1_rgb8_texture-basic.c
@@ -72,7 +72,12 @@ piglit_display(void)
     glCopyTexImage2D(GL_TEXTURE_2D, 0, format, 0, 0, width, height, 0);
     pass = piglit_check_gl_error(GL_INVALID_VALUE) && pass;
 
-    /* no subimage support */
+    /* From the GL_OES_compressed_ETC1_RGB8_texture spec:
+     *
+     *     INVALID_OPERATION is generated by CompressedTexSubImage2D,
+     *     TexSubImage2D, or CopyTexSubImage2D if the texture image <level>
+     *     bound to <target> has internal format ETC1_RGB8_OES.
+     */
     glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0,
             width, height, GL_RGB, GL_UNSIGNED_BYTE, fake_tex_data);
     pass = piglit_check_gl_error(GL_INVALID_OPERATION) && pass;
-- 
1.8.1.1