refactor bifacial merge, improve merge tests

docs/sphinx/source/whatsnew/v0.7.0.rst

@@ -7,7 +7,7 @@ This is a major release that drops support for Python 2 and Python 3.4. We
 recommend all users of v0.6.3 upgrade to this release after checking API
 compatibility notes.
 
-**Python 2.7 support ended on June 1, 2019**. (:issue:`501`)
+**Python 2.7 support ended on June 1, 2019.** (:issue:`501`)
 **Minimum numpy version is now 1.10.4. Minimum pandas version is now 0.18.1.**
 
 Bug fixes
@@ -18,10 +18,12 @@ Bug fixes
 Testing
 ~~~~~~~
 * Added 30 minutes to timestamps in `test_psm3.csv` to match change in NSRDB (:issue:`733`)
+* Added tests for methods in bifacial.py.
 
 
 Contributors
 ~~~~~~~~~~~~
 * Mark Campanellli (:ghuser:`markcampanelli`)
 * Will Holmgren (:ghuser:`wholmgren`)
 * Oscar Dowson (:ghuser:`odow`)
+* Alexander Morgan (:ghuser:`alexandermorgan`)

pvlib/bifacial.py

@@ -159,8 +159,7 @@ def build(report, pvarray):
         back surface of center pvrow (index=1)"""
         # Initialize the report as a dictionary
         if report is None:
-            list_keys = ['total_inc_back', 'total_inc_front']
-            report = {key: [] for key in list_keys}
+            report = {'total_inc_back': [], 'total_inc_front': []}
         # Add elements to the report
         if pvarray is not None:
             pvrow = pvarray.pvrows[1]  # use center pvrow
@@ -177,13 +176,12 @@ def build(report, pvarray):
 
     @staticmethod
     def merge(reports):
-        """Works for dictionary reports"""
+        """Works for dictionary reports. Merges the reports list of
+        dictionaries in a single dictionary. The list of the first
+        dictionary are extended by those of all subsequent lists."""
         report = reports[0]
-        # Merge only if more than 1 report
-        if len(reports) > 1:
-            keys_report = list(reports[0].keys())
-            for other_report in reports[1:]:
-                if other_report is not None:
-                    for key in keys_report:
-                        report[key] += other_report[key]
+        keys_report = list(report.keys())
+        for other_report in reports[1:]:  # loop won't run if len(reports) < 2
+            for key in keys_report:
+                report[key] += other_report[key]
         return report

pvlib/test/test_bifacial.py

@@ -1,6 +1,7 @@
 import pandas as pd
+import numpy as np
 from datetime import datetime
-from pvlib.bifacial import pvfactors_timeseries
+from pvlib.bifacial import pvfactors_timeseries, PVFactorsReportBuilder
 from conftest import requires_pvfactors
 import pytest
 
@@ -107,3 +108,43 @@ def test_pvfactors_timeseries_pandas_inputs(run_parallel_calculations):
 
     pd.testing.assert_series_equal(ipoa_front, expected_ipoa_front)
     pd.testing.assert_series_equal(ipoa_back, expected_ipoa_back)
+
+
+def test_build_1():
+    """Test that build correctly instantiates a dictionary, when passed a Nones
+    for the report and pvarray arguments.
+    """
+    report = None
+    pvarray = None
+    expected = {'total_inc_back': [np.nan], 'total_inc_front': [np.nan]}
+    assert expected == PVFactorsReportBuilder.build(report, pvarray)
+
+
+def test_merge_1():
+    """Test that merge correctly returns the first element of the reports
+    argument when there is only dictionary in reports.
+    """
+    test_dict = {'total_inc_back': [1, 2, 3], 'total_inc_front': [4, 5, 6]}
+    reports = [test_dict]
+    assert test_dict == PVFactorsReportBuilder.merge(reports)
+
+
+def test_merge_2():
+    """Test that merge correctly combines two dictionary reports.
+    """
+    test_dict_1 = {'total_inc_back': [1, 2], 'total_inc_front': [4, 5]}
+    test_dict_2 = {'total_inc_back': [3], 'total_inc_front': [6]}
+    expected = {'total_inc_back': [1, 2, 3], 'total_inc_front': [4, 5, 6]}
+    reports = [test_dict_1, test_dict_2]
+    assert expected == PVFactorsReportBuilder.merge(reports)
+
+
+def test_merge_3():
+    """Test that merge correctly combines three dictionary reports.
+    """
+    test_dict_1 = {'total_inc_back': [1], 'total_inc_front': [4]}
+    test_dict_2 = {'total_inc_back': [2], 'total_inc_front': [5]}
+    test_dict_3 = {'total_inc_back': [3], 'total_inc_front': [6]}
+    expected = {'total_inc_back': [1, 2, 3], 'total_inc_front': [4, 5, 6]}
+    reports = [test_dict_1, test_dict_2, test_dict_3]
+    assert expected == PVFactorsReportBuilder.merge(reports)