diff --git a/tests/basic_datetime_test.py b/tests/basic_datetime_test.py
index 7cec911..cb14e3c 100644
--- a/tests/basic_datetime_test.py
+++ b/tests/basic_datetime_test.py
@@ -16,7 +16,7 @@ class TestBasicDateInit(unittest.TestCase):
         self.assertEqual(fixed_date.year_quarter, 1)
 
     def test_date_init_february_last(self):
-        fixed_date = FixedDate(date=datetime.date(2022, 2, 25))
+        fixed_date = FixedDate(datetime.date(2022, 2, 25))
         self.assertEqual(fixed_date.date, datetime.date(2022, 2, 25))
         self.assertEqual(fixed_date.year, 2022)
         self.assertEqual(fixed_date.month, 2)
@@ -87,3 +87,7 @@ class TestBasicDateInit(unittest.TestCase):
     def test_init_with_invalid_parameter_combination(self):
         # day_of_year also requires year parameter
         self.assertRaises(ValueError, lambda : FixedDate(day_of_year=15))
+
+    def test_date_init_with_none_arguments(self):
+        fixed_date = FixedDate(datetime.date(2022, 1, 1), None, None, None, None)
+        self.assertEqual(fixed_date.date, datetime.date(2022, 1, 1))
diff --git a/tests/basic_day_of_year_test.py b/tests/basic_day_of_year_test.py
index a2eb284..d5eb740 100644
--- a/tests/basic_day_of_year_test.py
+++ b/tests/basic_day_of_year_test.py
@@ -1,4 +1,5 @@
 import unittest
+import datetime
 from fixedcal.core.date import FixedDate
 
 class TestBasicDayOfYearInit(unittest.TestCase):
@@ -33,3 +34,14 @@ class TestBasicDayOfYearInit(unittest.TestCase):
         self.assertEqual(fixed_date.month, 13)
         self.assertEqual(fixed_date.day_of_month, 29)
         self.assertTrue(fixed_date.is_year_day)
+
+    def test_init_day_of_year_with_none_arguments(self):
+        fixed_date = FixedDate(None, 1, None, None, 2022)
+        self.assertEqual(fixed_date.date, datetime.date(2022, 1, 1))
+
+    def test_day_of_year_init_all_days(self):
+        year_start = datetime.date(2024, 1, 1)  # leap year
+        for day_of_year in range(1, 367):
+            fixed_date = FixedDate(day_of_year=day_of_year, year=2024)
+            native_date = year_start + datetime.timedelta(days=day_of_year-1)
+            self.assertEqual(fixed_date.date, native_date)
diff --git a/tests/fixed_date_init_test.py b/tests/fixed_date_init_test.py
index 63f1443..e1fe2db 100644
--- a/tests/fixed_date_init_test.py
+++ b/tests/fixed_date_init_test.py
@@ -52,3 +52,7 @@ class TestInitWithFixedDate(unittest.TestCase):
 
     def test_month_too_big_raises(self):
         self.assertRaises(ValueError, lambda : FixedDate(day=15, month=14, year=2022))
+
+    def test_day_month_year_init_with_none_arguments(self):
+        fixed_date = FixedDate(None, None, 1, 1, 2022)
+        self.assertEqual(fixed_date.date, datetime.date(2022, 1, 1))