tests: Add support for skipping tests, skip EIO tests if not enabled

The EIO tests depend on the EIO support from the "encumbered"
repository, which means that they are not normally built with
gem5. This causes all EIO related tests to fail, which is both
annoying and confusing. This patch addresses this by adding support
for skipping tests if certain conditions (e.g., the presence of a
SimObject) can not be met. It introduces the following Python
functions that can be called from within a test case:

  * skip_test -- Skip a test and optionally print why the test was
                 skipped.

  * has_sim_object -- Test if a SimObject exists.

  * require_sim_object -- Test if a SimObject exists and skip, or
                          optionally fail, the test if not.

Additionally, this patch updates the EIO tests to check for the
presence of EioProcess.

tests/SConscript

@@ -150,6 +150,9 @@ def run_test(target, source, env):
                 # Hand the return status to scons and let scons decide what
                 # to do about it (typically terminate unless run with -k).
                 return status
+        elif status == 2:
+            # The test was skipped
+            pass
         else:
             print 'M5 exited with non-zero status', status
         # complete but failed execution (call to exit() with non-zero
@@ -159,6 +162,8 @@ def run_test(target, source, env):
     # Generate status file contents based on exit status of m5 or diff-out
     if status == 0:
         status_str = "passed."
+    elif status == 2:
+        status_str = "skipped."
     else:
         status_str = "FAILED!"
     f = file(str(target[0]), 'w')
@@ -188,6 +193,8 @@ def print_test(target, source, env):
         status = termcap.Red + status[:-1] + termcap.Normal + status[-1]
     elif status == "passed.":
         status = termcap.Green + status[:-1] + termcap.Normal + status[-1]
+    elif status == "skipped.":
+        status = termcap.Yellow + status[:-1] + termcap.Normal + status[-1]
 
     # put it back in the list and join with space
     words[-1] = status

tests/quick/se/20.eio-short/test.py

@@ -26,6 +26,8 @@
 #
 # Authors: Steve Reinhardt
 
+require_sim_object("EioProcess")
+
 root.system.cpu.workload = EioProcess(file = binpath('anagram',
                                                      'anagram-vshort.eio.gz'))
 root.system.cpu.max_insts_any_thread = 500000

tests/quick/se/30.eio-mp/test.py

@@ -26,6 +26,8 @@
 #
 # Authors: Lisa Hsu
 
+require_sim_object("EioProcess")
+
 process = EioProcess(file = binpath('anagram', 'anagram-vshort.eio.gz'))
 
 for i in xrange(nb_cores):

tests/run.py

@@ -1,3 +1,15 @@
+# Copyright (c) 2012 ARM Limited
+# All rights reserved
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
 # Copyright (c) 2006-2007 The Regents of The University of Michigan
 # All rights reserved.
 #
@@ -35,6 +47,52 @@ from os.path import join as joinpath
 
 import m5
 
+def skip_test(reason=""):
+    """Signal that a test should be skipped and optionally print why.
+
+    Keyword arguments:
+      reason -- Reason why the test failed. Output is omitted if empty.
+    """
+
+    if reason:
+        print "Skipping test: %s" % reason
+    sys.exit(2)
+
+def has_sim_object(name):
+    """Test if a SimObject exists in the simulator.
+
+    Arguments:
+      name -- Name of SimObject (string)
+
+    Returns: True if the object exists, False otherwise.
+    """
+
+    try:
+        cls = getattr(m5.objects, name)
+        return issubclass(cls, m5.objects.SimObject)
+    except AttributeError:
+        return False
+
+def require_sim_object(name, fatal=False):
+    """Test if a SimObject exists and abort/skip test if not.
+
+    Arguments:
+      name -- Name of SimObject (string)
+
+    Keyword arguments:
+      fatal -- Set to True to indicate that the test should fail
+               instead of being skipped.
+    """
+
+    if has_sim_object(name):
+        return
+    else:
+        msg = "Test requires the '%s' SimObject." % name
+        if fatal:
+            m5.fatal(msg)
+        else:
+            skip_test(msg)
+
 # Since we're in batch mode, dont allow tcp socket connections
 m5.disableAllListeners()