Add tests for the recent resource module change.

Also add a test that Python doesn't die with SIGXFSZ if it exceeds the
file rlimit.  (Assuming this will also test the behavior when the 2GB
limit is exceed on a platform that doesn't have large file support.)

Lib/test/output/test_resource

+test_resource
+True

Lib/test/test_resource.py

+import os
+import resource
+
+from test_support import TESTFN
+
+# This test is checking a few specific problem spots.  RLIMIT_FSIZE
+# should be RLIM_INFINITY, which will be a really big number on a
+# platform with large file support.  On these platforms, we need to
+# test that the get/setrlimit functions properly convert the number to
+# a C long long and that the conversion doesn't raise an error.
+
+try:
+    cur, max = resource.getrlimit(resource.RLIMIT_FSIZE)
+except AttributeError:
+    pass
+else:
+    print resource.RLIM_INFINITY == max
+    resource.setrlimit(resource.RLIMIT_FSIZE, (cur, max))
+
+# Now check to see what happens when the RLIMIT_FSIZE is small.  Some
+# versions of Python were terminated by an uncaught SIGXFSZ, but
+# pythonrun.c has been fixed to ignore that exception.  If so, the
+# write() should return EFBIG when the limit is exceeded.
+
+try:
+    resource.setrlimit(resource.RLIMIT_FSIZE, (1024, max))
+    f = open(TESTFN, "wb")
+    f.write("X" * 1024)
+    try:
+        f.write("Y")
+        f.flush()
+    except IOError:
+        pass
+    f.close()
+    os.unlink(TESTFN)
+finally:
+    resource.setrlimit(resource.RLIMIT_FSIZE, (cur, max))
+
+# And be sure that setrlimit is checking for really large values
+too_big = 10L**50
+try:
+    resource.setrlimit(resource.RLIMIT_FSIZE, (too_big, max))
+except OverflowError:
+    pass
+try:
+    resource.setrlimit(resource.RLIMIT_FSIZE, (max, too_big))
+except OverflowError:
+    pass