[PATCH] Netperf: fix confidence parsing when throughput measurement is 0

[Jan Tluka]

Netperf does not properly handle confidence calculation when measured
throughput is 0. E.g. when firewall blocks the data stream. When this
happens netperf reports -nan for confidence level instead of some
reasonable number. This patch adds exception check while parsing confidence
levels.

Fixes #170.

Signed-off-by: Jan Tluka 
---
 test_modules/Netperf.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/test_modules/Netperf.py b/test_modules/Netperf.py
index 7b9d7f7..5f00d54 100644
--- a/test_modules/Netperf.py
+++ b/test_modules/Netperf.py
@@ -223,7 +223,14 @@ class Netperf(TestGeneric):
     def _parse_confidence_omni(self, output):
         pattern_throughput_confid = "THROUGHPUT_CONFID=([-]?\d+.\d+)"
         pattern_confidence_level = "CONFIDENCE_LEVEL=(\d+)"
-        throughput_confid = float(re.search(pattern_throughput_confid, output).group(1))
+        try:
+            throughput_confid = float(re.search(pattern_throughput_confid, output).group(1))
+        except AttributeError:
+            # when netperf measures throughput=0 it tries to divide by 0 and
+            # prints THROUGHPUT_CONFID=-nan
+            logging.warning("Could not parse THROUGHPUT_CONFID")
+            return (0, 0.0)
+
         confidence_level = int(re.search(pattern_confidence_level, output).group(1))

real_confidence = (confidence_level, throughput_confid/2)