Revert "Revert "adding CountriesColumnMerger""

This reverts commit a80caa2361.

src/CountriesColumnMerger.py

@@ -0,0 +1,10 @@
+from CountriesMerger import CountriesMerger
+
+class CountriesColumnMerger:
+
+    @staticmethod
+    def mergeCountriesColumnOfSrcIntoCountriesColumnOfDst(src, dst):
+        COUNTRIES = 'Countries'
+        dst[COUNTRIES] = CountriesMerger.mergeSrcIntoDst(
+            dst = dst[COUNTRIES],
+            src = src[COUNTRIES])

src/CountriesColumnMergerTest.py

@@ -0,0 +1,53 @@
+import unittest
+import pandas as pd
+from pandas.testing import assert_frame_equal
+from TestHelper import TestHelper
+from src.CountriesColumnMerger import CountriesColumnMerger
+
+class CountriesColumnMergerTest(unittest.TestCase):
+
+    def test_mergeCountriesColumnOfSrcIntoCountriesColumnOfDst(self):
+        # Given
+        dst = TestHelper.createDataFrame(
+                columns = ['Countries'],
+                data = [  [[]],
+                          [['France', 'United Kingdom']],
+                          [['France']]],
+                index = pd.Index(
+                    [
+                        '016M20A',
+                        '030L20B',
+                        '030L20A'
+                    ],
+                    name = 'VAX_LOT'))
+
+        src = TestHelper.createDataFrame(
+                columns = ['Countries'],
+                data = [  [['Germany']],
+                          [['DummyCountry']]],
+                index = pd.Index(
+                    [
+                        '030L20B',
+                        'dummyVaxLot'
+                    ],
+                    name = 'VAX_LOT'))
+        
+        # When
+        CountriesColumnMerger.mergeCountriesColumnOfSrcIntoCountriesColumnOfDst(dst = dst, src = src)
+
+        # Then
+        assert_frame_equal(
+            dst,
+            TestHelper.createDataFrame(
+                columns = ['Countries'],
+                data = [  [[]],
+                          [['France', 'Germany', 'United Kingdom']],
+                          [['France']]],
+                index = pd.Index(
+                    [
+                        '016M20A',
+                        '030L20B',
+                        '030L20A'
+                    ],
+                    name = 'VAX_LOT')),
+            check_dtype = True)