Add unit tests for datetime, file, and YAML utility functions

Author: marcarl

test/test_datetime_utils.py

@@ -0,0 +1,148 @@
+#!/usr/bin/env python3
+"""
+Tests for datetime utility functions.
+"""
+
+import pytest
+from util.datetime_utils import format_datetime, format_datetime_for_git, MIN_GIT_YEAR
+
+
+# ===========================================================================
+# format_datetime Tests
+# ===========================================================================
+
+@pytest.mark.unit
+class TestFormatDatetime:
+    """Test the format_datetime function."""
+
+    def test_format_datetime_with_time(self):
+        """Test formatting datetime with time component (should strip time)."""
+        result = format_datetime("2024-03-15T14:30:00")
+        assert result == "2024-03-15"
+
+    def test_format_datetime_date_only(self):
+        """Test formatting date without time component."""
+        result = format_datetime("2024-03-15")
+        assert result == "2024-03-15"
+
+    def test_format_datetime_with_timezone(self):
+        """Test formatting datetime with timezone (should strip it)."""
+        result = format_datetime("2024-03-15T14:30:00+01:00")
+        assert result == "2024-03-15"
+
+    def test_format_datetime_none(self):
+        """Test that None input returns None."""
+        result = format_datetime(None)
+        assert result is None
+
+    def test_format_datetime_empty_string(self):
+        """Test that empty string returns None."""
+        result = format_datetime("")
+        assert result is None
+
+    def test_format_datetime_invalid_format(self):
+        """Test invalid datetime format returns original string."""
+        invalid_input = "not-a-valid-date"
+        result = format_datetime(invalid_input)
+        assert result == invalid_input
+
+
+# ===========================================================================
+# format_datetime_for_git Tests
+# ===========================================================================
+
+@pytest.mark.unit
+class TestFormatDatetimeForGit:
+    """Test the format_datetime_for_git function."""
+
+    def test_valid_datetime_with_time(self):
+        """Test formatting valid datetime with time component."""
+        result = format_datetime_for_git("2024-03-15T14:30:00")
+        assert result == "2024-03-15T14:30:00"
+
+    def test_datetime_with_z_timezone(self):
+        """Test formatting datetime with Z (Zulu/UTC) timezone."""
+        result = format_datetime_for_git("2024-03-15T14:30:00Z")
+        assert result == "2024-03-15T14:30:00"
+
+    def test_date_only_adds_midnight_time(self):
+        """Test that date without time gets midnight time added."""
+        result = format_datetime_for_git("2024-03-15")
+        assert result == "2024-03-15T00:00:00"
+
+    def test_date_before_min_git_year(self):
+        """Test that dates before MIN_GIT_YEAR are clamped to MIN_GIT_YEAR."""
+        # 1969 < MIN_GIT_YEAR (1980)
+        result = format_datetime_for_git("1969-01-01")
+        assert result == f"{MIN_GIT_YEAR}-01-01T00:00:00"
+        assert result.startswith("1980")
+
+    def test_date_before_min_git_year_with_time(self):
+        """Test that datetime before MIN_GIT_YEAR is clamped (with time)."""
+        result = format_datetime_for_git("1975-06-15T12:30:00")
+        assert result == f"{MIN_GIT_YEAR}-01-01T00:00:00"
+
+    def test_very_old_date(self):
+        """Test very old dates (e.g., 1800s) are clamped to MIN_GIT_YEAR."""
+        result = format_datetime_for_git("1850-01-01")
+        assert result == f"{MIN_GIT_YEAR}-01-01T00:00:00"
+
+    def test_none_value(self):
+        """Test that None input returns None."""
+        result = format_datetime_for_git(None)
+        assert result is None
+
+    def test_empty_string(self):
+        """Test that empty string returns None."""
+        result = format_datetime_for_git("")
+        assert result is None
+
+    def test_invalid_format_fallback(self):
+        """Test invalid datetime format raises ValueError."""
+        # If it's not a valid ISO format and can't be parsed, raises ValueError
+        with pytest.raises(ValueError):
+            format_datetime_for_git("not-a-date")
+
+    def test_date_at_min_git_year_boundary(self):
+        """Test date exactly at MIN_GIT_YEAR boundary."""
+        result = format_datetime_for_git(f"{MIN_GIT_YEAR}-01-01")
+        assert result == f"{MIN_GIT_YEAR}-01-01T00:00:00"
+
+    def test_date_one_year_before_min(self):
+        """Test date one year before MIN_GIT_YEAR."""
+        result = format_datetime_for_git(f"{MIN_GIT_YEAR - 1}-12-31")
+        assert result == f"{MIN_GIT_YEAR}-01-01T00:00:00"
+
+
+# ===========================================================================
+# Edge Cases
+# ===========================================================================
+
+@pytest.mark.unit
+class TestDatetimeEdgeCases:
+    """Test edge cases for datetime utilities."""
+
+    def test_leap_year_date(self):
+        """Test handling of leap year dates."""
+        result = format_datetime("2024-02-29")
+        assert result == "2024-02-29"
+
+        result_git = format_datetime_for_git("2024-02-29T23:59:59")
+        assert result_git == "2024-02-29T23:59:59"
+
+    def test_end_of_year_date(self):
+        """Test handling of end-of-year dates."""
+        result = format_datetime_for_git("2024-12-31T23:59:59")
+        assert result == "2024-12-31T23:59:59"
+
+    def test_various_datetime_formats(self):
+        """Test various valid ISO datetime formats."""
+        test_cases = [
+            ("2024-01-01", "2024-01-01"),
+            ("2024-06-15T12:00:00", "2024-06-15"),
+            ("2024-12-31T23:59:59Z", "2024-12-31"),
+        ]
+
+        for input_dt, expected in test_cases:
+            result = format_datetime(input_dt)
+            assert result == expected