Set the date and interval styles of pymeos_initialize from their names

pymeos/meos_init.py

@@ -6,6 +6,7 @@
     meos_set_datestyle,
     meos_set_intervalstyle,
 )
+from pymeos_cffi.functions import _ffi
 
 
 def pymeos_initialize(
@@ -29,13 +30,13 @@ def pymeos_initialize(
 
     if date_style is not None:
         if isinstance(date_style, str):
-            meos_set_datestyle(date_style, None)
+            meos_set_datestyle(date_style, _ffi.NULL)
         else:
             meos_set_datestyle(*date_style)
 
     if interval_style is not None:
         if isinstance(interval_style, str):
-            meos_set_intervalstyle(interval_style, None)
+            meos_set_intervalstyle(interval_style, 0)
         else:
             meos_set_intervalstyle(*interval_style)
 

tests/meos_init_test.py

@@ -0,0 +1,38 @@
+import pytest
+from pymeos_cffi import meos_get_datestyle, meos_get_intervalstyle
+
+from pymeos import pymeos_initialize
+from tests.conftest import TestPyMEOS
+
+
+# Laid out as #TestTInterpolation; each test restores the styles it changes, since
+# every other test runs under the styles conftest initializes.
+class TestPyMEOSInitialize(TestPyMEOS):
+    @pytest.mark.parametrize(
+        "date_style, expected",
+        [
+            ("SQL, DMY", "SQL, DMY"),
+            ("German", "German, DMY"),
+            ("Postgres, MDY", "Postgres, MDY"),
+        ],
+        ids=["SQL DMY", "German", "Postgres MDY"],
+    )
+    def test_date_style(self, date_style, expected):
+        previous = meos_get_datestyle()
+        try:
+            pymeos_initialize("UTC", date_style=date_style)
+            assert meos_get_datestyle() == expected
+        finally:
+            pymeos_initialize("UTC", date_style=previous)
+
+    @pytest.mark.parametrize(
+        "interval_style",
+        ["postgres", "postgres_verbose", "sql_standard", "iso_8601"],
+    )
+    def test_interval_style(self, interval_style):
+        previous = meos_get_intervalstyle()
+        try:
+            pymeos_initialize("UTC", interval_style=interval_style)
+            assert meos_get_intervalstyle() == interval_style
+        finally:
+            pymeos_initialize("UTC", interval_style=previous)