finalized helper functions for category trees; started writing tests

tests/test_category_edge_cases.py

@@ -1,4 +1,5 @@
 from datetime import date
+from decimal import Decimal
 
 import pytest
 
@@ -12,24 +13,30 @@ class TestCategoryComputedFields:
     def test_hash_id_computed_field_simple(self):
         """Test hash_id for single-level category."""
         c = Category.from_str("single")
+        assert c
         assert hasattr(c, "hash_id")
         assert isinstance(c.hash_id, str)
         # Hash should be deterministic for same inputs
         c2 = Category.from_str("single")
+        assert c2
         assert c.hash_id == c2.hash_id
 
     def test_hash_id_computed_field_nested(self):
         """Test hash_id for multi-level category hierarchy."""
         c1 = Category.from_str("level1:level2:level3")
+        assert c1
         assert hasattr(c1, "hash_id")
 
         c2 = Category.from_str("level1:level2:level3")
+        assert c2
         assert c1.hash_id == c2.hash_id
 
     def test_hash_id_different_hierarchy(self):
         """Test that different hierarchies have different hash_ids."""
         c1 = Category.from_str("A:B")
         c2 = Category.from_str("A:C")
+        assert c1
+        assert c2
         # Different last level -> different hash_id
         assert c1.hash_id != c2.hash_id
 
@@ -40,22 +47,26 @@ class TestCategoryComputedFields:
 
         # Create another with same name but no parent
         orphan = Category.from_str("Budget")
+        assert orphan
 
         assert cat1.hash_id != orphan.hash_id
 
     def test_to_str_single_level(self):
         """Test to_str() for single-level category."""
         c = Category.from_str("single")
+        assert c
         assert c.to_str() == "single"
 
     def test_to_str_nested(self):
         """Test to_str() for nested category."""
         c = Category.from_str("parent:child:grandchild")
+        assert c
         assert c.to_str() == "parent:child:grandchild"
 
     def test_str_uses_to_str(self):
         """Test that __str__ delegates to to_str()."""
         c = Category.from_str("A:B:C")
+        assert c
         assert str(c) == c.to_str() == "A:B:C"
 
     def test_repr_simple(self):
@@ -79,7 +90,7 @@ class TestCategoryBudgetValidation:
         cat = CategoryFactory.build()
         budget = CategoryBudget(
             category=cat,
-            amount_eur=100.00,
+            amount_eur=Decimal("100.00"),
         )
         assert budget.valid_from is None
         assert budget.valid_to is None
@@ -90,7 +101,7 @@ class TestCategoryBudgetValidation:
         cat = CategoryFactory.build()
         budget = CategoryBudget(
             category=cat,
-            amount_eur=100.00,
+            amount_eur=Decimal("100.00"),
             valid_from=date(2026, 10, 1),
             valid_to=date(2026, 10, 31),
         )
@@ -105,7 +116,7 @@ class TestCategoryBudgetValidation:
         with pytest.raises(ValueError) as exc_info:
             CategoryBudget(
                 category=cat,
-                amount_eur=100.00,
+                amount_eur=Decimal("100.00"),
                 valid_from=date(2026, 10, 31),
                 valid_to=date(2026, 10, 1),
             )
@@ -120,7 +131,7 @@ class TestCategoryBudgetValidation:
         cat = CategoryFactory.build()
         budget = CategoryBudget(
             category=cat,
-            amount_eur=100.00,
+            amount_eur=Decimal("100.00"),
             valid_from=date(2026, 10, 1),
             valid_to=date(2026, 10, 1),
         )
@@ -133,7 +144,7 @@ class TestCategoryBudgetValidation:
         cat = CategoryFactory.build()
         budget = CategoryBudget(
             category=cat,
-            amount_eur=150.75,
+            amount_eur=Decimal("150.75"),
             valid_from=date(2026, 9, 1),
             valid_to=date(2026, 9, 30),
         )
@@ -142,7 +153,7 @@ class TestCategoryBudgetValidation:
         try:
             CategoryBudget(
                 category=cat,
-                amount_eur=200.00,
+                amount_eur=Decimal("200.00"),
                 valid_from=date(2026, 12, 31),
                 valid_to=date(2026, 12, 30),
             )