t/jobs/t0030: add test for --bandwidth-log option

Add a test to detect changes that break the --bandwidth-log option. This
option uses the logging data structures in a way that differs from how
the other logs use them. So it's easy to forget about this special case.

Recent patches resolving related breakage are:
d722447 ("stat: fix segfault with fio
option --bandwidth-log")
acc481b ("iolog: fix reported defect
from coverity scan")

Signed-off-by: Vincent Fu <vincent.fu@samsung.com>

t/jobs/t0030.fio

@@ -0,0 +1,10 @@
+# run with --bandwidth-log
+# broken behavior: seg fault
+# successful behavior: test runs to completion with 0 as the exit code
+
+[test]
+ioengine=null
+filesize=1T
+rw=read
+time_based
+runtime=2s

t/run-fio-tests.py

@@ -859,6 +859,16 @@ def check_result(self):
         'output_format':    'json',
         'requirements':     [],
     },
+    {
+        'test_id':          30,
+        'test_class':       FioJobFileTest,
+        'job':              't0030.fio',
+        'success':          SUCCESS_DEFAULT,
+        'pre_job':          None,
+        'pre_success':      None,
+        'parameters':       ['--bandwidth-log'],
+        'requirements':     [],
+    },
     {
         'test_id':          1000,
         'test_class':       FioExeTest,