framework/test/opengl.py: Add environment variable to turn off fast skipping

Setting PIGLIT_NO_FAST_SKIP will disable the fast skipping mechanism
altogether.

It does this by shadowing FastSkipMixin at import time. This method is
robust and cheap, but makes testing difficult.

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>

2 files changed, 32 insertions, 0 deletions

diff --git a/README b/README
index e48c23dd0..28d9ec5fb 100644
--- a/README
+++ b/README
@@ -297,6 +297,13 @@ behaves.
       glslparsertest. This can be used to test ES<x>_COMPATABILITY extensions
       for OpenGL
 
+ PIGLIT_NO_FAST_SKIP
+       Piglit has a mechanism run in the python layer for skipping tests with
+       unmet OpenGL or window system dependencies without starting a new
+       process (which is expensive). Sometimes this system doesn't work or is
+       undesirable, setting this environment variable to True will disable this
+       system.
+
 3.2 Note
 --------
 
diff --git a/framework/test/opengl.py b/framework/test/opengl.py
index 9cad32cd1..af0cc560b 100644
--- a/framework/test/opengl.py
+++ b/framework/test/opengl.py
@@ -24,6 +24,7 @@ from __future__ import absolute_import, division, print_function
 import errno
 import os
 import subprocess
+import warnings
 
 from framework import exceptions, core
 from framework.options import OPTIONS
@@ -35,6 +36,10 @@ __all__ = [
     'FastSkipMixin',
 ]
 
+# An environment variable that when set to true disables the FastSkipMixin by
+# stubbing it out
+_DISABLED = bool(os.environ.get('PIGLIT_NO_FAST_SKIP', False))
+
 
 class StopWflinfo(exceptions.PiglitException):
     """Exception called when wlfinfo getter should stop."""
@@ -364,3 +369,23 @@ class FastSkipMixin(object):
                     self.glsl_es_version, self.__info.glsl_es_version))
 
         super(FastSkipMixin, self).is_skip()
+
+
+class FastSkipMixinDisabled(object):
+    def __init__(self, *args, **kwargs):
+        # Tests that implement the FastSkipMixin expect to have these values
+        # set, so just fill them in with the default values.
+        self.gl_required = set()
+        self.gl_version = None
+        self.gles_version = None
+        self.glsl_version = None
+        self.glsl_es_version = None
+
+        super(FastSkipMixinDisabled, self).__init__(*args, **kwargs)
+
+
+# Shadow the real FastSkipMixin with the Disabled version if
+# PIGLIT_NO_FAST_SKIP is truthy
+if _DISABLED:
+    warnings.warn('Fast Skipping Disabled')
+    FastSkipMixin = FastSkipMixinDisabled