Add handling for ZeroDivisionError (#76)

* Add handling for ZeroDivisionError

* Changes from session with Mehul

.gitignore

@@ -47,3 +47,4 @@ MANIFEST
 
 # Per-project virtualenvs
 .venv*/
+venv*/

README.md

@@ -9,8 +9,8 @@ It is suggested to use a venv to install and run touchstone.
 ```shell
 python -m venv /virtual/environment
 source /virtual/environment/bin/activate
-git clone https://github.com/cloud-bulldozer/touchstone
-cd touchstone
+git clone https://github.com/cloud-bulldozer/benchmark-comparison
+cd benchmark-comparison
 python setup.py develop
 touchstone_compare -h
 usage: touchstone_compare [-h] [--version] [--database {elasticsearch}] [--identifier-key IDENTIFIER] -u UUID [UUID ...] [-a ALIASES [ALIASES ...]] [-o {json,yaml,csv}] --config CONFIG [--output-file OUTPUT_FILE]

src/touchstone/decision_maker/__init__.py

@@ -29,18 +29,29 @@ def _compare(self, input_dict, compare_dict):
         # baseline value is the current value plus the tolerancy
         base_val = input_dict[self.baseline_uuid] + input_dict[self.baseline_uuid] * self.tolerancy / 100
         for u, v in input_dict.items():
+            # skip input_dict values that are part of the baseline uuid (no comparison to self)
             if u == self.baseline_uuid:
                 continue
-            metric_percent = v * 100 / input_dict[self.baseline_uuid]
-            # If percentage is greater than 100, sustract 100 from it else substract it from 100
-            deviation = metric_percent - 100 if metric_percent > 100 else 100 - metric_percent
-            deviation = -deviation if v < input_dict[self.baseline_uuid] else deviation
-            if (self.tolerancy >= 0 and v > base_val) or (self.tolerancy < 0 and v < base_val):
-                result = "Fail"
-                self.passed = False
-                self.fails += 1
-            else:
-                result = "Pass"
+            try:
+                metric_percent = v * 100 / input_dict[self.baseline_uuid]
+            except ZeroDivisionError:
+                # both values are 0
+                if (v == 0) and (input_dict[self.baseline_uuid] == 0):
+                    metric_percent = 100
+                # just baseline value is 0
+                else:
+                    metric_percent = 0
+            finally:
+                # If percentage is greater than 100, sustract 100 from it else substract it from 100
+                deviation = metric_percent - 100 if metric_percent > 100 else 100 - metric_percent
+                deviation = -deviation if v < input_dict[self.baseline_uuid] else deviation
+                print(f"deviation is {deviation}")
+                if (self.tolerancy >= 0 and v > base_val) or (self.tolerancy < 0 and v < base_val):
+                    result = "Fail"
+                    self.passed = False
+                    self.fails += 1
+                else:
+                    result = "Pass"
             if result not in compare_dict:
                 compare_dict[result] = {}
             compare_dict[result] = {