Merge pull request #14 from ymyke/bugfix/all_pos_neg

Fix two bugs related to handling all positive/negative values
tarioch · Sep 6, 2020 · 9d046ac · 9d046ac
2 parents 0367b05 + a626a40
commit 9d046ac
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Showing 2 changed files with 7 additions and 6 deletions.
diff --git a/src/xirr/math.py b/src/xirr/math.py
@@ -38,13 +38,13 @@ def xirr(valuesPerDate):
     >>> xirr(valuesPerDate)
     -0.645363882724717
     '''
-    if not valuesPerDate or len(valuesPerDate) < 2:
+    if not valuesPerDate:
         return None
 
     if all(v >= 0 for v in valuesPerDate.values()):
-        return -float("inf")
-    if all(v <= 0 for v in valuesPerDate.values()):
         return float("inf")
+    if all(v <= 0 for v in valuesPerDate.values()):
+        return -float("inf")
 
     result = None
     try:

diff --git a/tests/test_math.py b/tests/test_math.py
@@ -10,14 +10,15 @@
     ({'2020-03-12': 65209.6, '2019-12-31': -80005.8}, -0.6454),
     ({'2019-12-31': -100082.76, '2020-03-05': 82671.24}, -0.6581),
     ({}, None),
-    ({'2019-12-31': -100082.76}, None),
+    ({'2019-12-31': -100082.76}, -float("inf")),
+    ({'2022-10-12': 200}, float("inf")),
     ({'2019-12-31': -0.00001, '2020-03-05': 0.00001}, 0.0),
     ({'2019-12-31': -100, '2020-03-05': 100}, 0.0),
     ({'2019-12-31': -100, '2020-03-05': 1000}, 412461.6383),
     ({'2017-12-16': -2236.3994659663, '2017-12-26': -47.3417585212, '2017-12-29': -46.52619316339632, '2017-12-31': 10424.74612565936, '2017-12-20': -13.077972551952}, 1.2238535289956518e+16),
     ({'2018-05-09': -200, '2018-06-09': 30, '2018-11-09': 50, '2018-12-09': 20}, -0.8037),
-    ({'2011-01-01': -1, '2011-01-02': 0, '2012-01-01': -1}, float("inf")),
-    ({'2011-01-01': 1, '2011-01-02': 0, '2012-01-01': 1}, -float("inf")),
+    ({'2011-01-01': -1, '2011-01-02': 0, '2012-01-01': -1}, -float("inf")),
+    ({'2011-01-01': 1, '2011-01-02': 0, '2012-01-01': 1}, float("inf")),
     ({'2011-07-01': -10000, '2014-07-01': 1}, -0.9535),
     ({'2011-07-01': 10000, '2014-07-01': -1}, -0.9535),
 ])