Moved frequency test from test_fincal

Added tests for Series class

tests/test_core.py

@@ -0,0 +1,49 @@
+import datetime
+
+from fincal.core import AllFrequencies, Frequency, Series
+from fincal.fincal import create_date_series
+
+
+class TestFrequency:
+    def test_creation(self):
+        D = Frequency('daily', 'days', 1, 1, 'D')
+        assert D.days == 1
+        assert D.symbol == 'D'
+        assert D.name == 'daily'
+        assert D.value == 1
+        assert D.freq_type == 'days'
+
+
+class TestAllFrequencies:
+    def test_attributes(self):
+        assert hasattr(AllFrequencies, 'D')
+        assert hasattr(AllFrequencies, 'M')
+        assert hasattr(AllFrequencies, 'Q')
+
+    def test_days(self):
+        assert AllFrequencies.D.days == 1
+        assert AllFrequencies.M.days == 30
+        assert AllFrequencies.Q.days == 91
+
+    def test_symbol(self):
+        assert AllFrequencies.H.symbol == 'H'
+        assert AllFrequencies.W.symbol == 'W'
+
+    def test_values(self):
+        assert AllFrequencies.H.value == 6
+        assert AllFrequencies.Y.value == 1
+
+    def test_type(self):
+        assert AllFrequencies.Q.freq_type == 'months'
+        assert AllFrequencies.W.freq_type == 'days'
+
+
+class TestSeries:
+    def test_creation(self):
+        series = Series([1, 2, 3, 4, 5, 6, 7], data_type=int)
+        assert series.dtype == float
+        assert series[2] == 3
+
+        dates = create_date_series('2021-01-01', '2021-01-31', 'D')
+        series = Series(dates, data_type=datetime.datetime)
+        assert Series.dtype == datetime.datetime