diff --git a/tests/test_category.py b/tests/test_category.py
index 8a197fc..9677d39 100644
--- a/tests/test_category.py
+++ b/tests/test_category.py
@@ -14,4 +14,85 @@ class CategoryTestCase(CashbookTestCase):
     'Test cashbook category module'
     module = 'cashbook_bookcategory'
 
+    @with_transaction()
+    def test_bookcategory_create(self):
+        """ add categories
+        """
+        BookCategory = Pool().get('cashbook.bookcategory')
+
+        company = self.prep_company()
+        with Transaction().set_context({
+            'company': company.id,
+            }):
+            categories, = BookCategory.create([{
+                'name': 'Cat 0',
+                'childs': [('create', [{
+                    'name': 'Cat 1'
+                    }, {
+                    'name': 'Cat 2'
+                    }])],
+                }])
+
+            cat2 = BookCategory.search([])
+            self.assertEqual(len(cat2), 3)
+            self.assertEqual(cat2[0].rec_name, 'Cat 0')
+            self.assertEqual(cat2[1].rec_name, 'Cat 0 / Cat 1')
+            self.assertEqual(cat2[2].rec_name, 'Cat 0 / Cat 2')
+
+            # delete single category
+            BookCategory.delete([cat2[2]])
+
+            # delete tree
+            BookCategory.delete([cat2[0]])
+
+    @with_transaction()
+    def test_bookcategory_add_to_cashbook(self):
+        """ add categories, link to cashbook
+        """
+        pool = Pool()
+        BookCategory = pool.get('cashbook.bookcategory')
+        Book = pool.get('cashbook.book')
+
+        types = self.prep_type()
+        company = self.prep_company()
+        with Transaction().set_context({
+            'company': company.id,
+            }):
+            category, = BookCategory.create([{
+                'name': 'Cat 0',
+                'childs': [('create', [{
+                    'name': 'Cat 1'
+                    }, {
+                    'name': 'Cat 2'
+                    }])],
+                }])
+
+            book, = Book.create([{
+                'name': 'Book 1',
+                'btype': types.id,
+                'currency': company.currency.id,
+                'number_sequ': self.prep_sequence().id,
+                'categories': [('add', [category.id])],
+                }])
+            self.assertEqual(book.rec_name, 'Book 1 | 0.00 usd | Open')
+            self.assertEqual(len(book.categories), 1)
+            self.assertEqual(book.categories[0].rec_name, 'Cat 0')
+
+            # replace category
+            Book.write(*[
+                [book],
+                {
+                    'categories': [
+                        ('remove', [category.id]),
+                        ('add', [category.childs[0].id]),
+                        ],
+                }])
+            self.assertEqual(len(book.categories), 1)
+            self.assertEqual(book.categories[0].rec_name, 'Cat 0 / Cat 1')
+
+            # delete all categories, this will unlink it from cashbook
+            BookCategory.delete([category])
+
+            self.assertEqual(len(book.categories), 0)
+
 # end CategoryTestCase