Add backend support for transaction categories (#524)

* Add backend support for transaction categories

* Fix tests

* Localize default category names

* Add tests

* Remove category icon and set default color

test/models/family_test.rb

@@ -30,6 +30,12 @@ class FamilyTest < ActiveSupport::TestCase
     end
   end
 
+  test "should destroy dependent transaction categories" do
+    assert_difference("Transaction::Category.count", -@family.transaction_categories.count) do
+      @family.destroy
+    end
+  end
+
   test "should calculate total assets" do
     assert_equal BigDecimal("25550"), @family.assets
   end

test/models/transaction/category_test.rb

@@ -0,0 +1,35 @@
+require "test_helper"
+
+class Transaction::CategoryTest < ActiveSupport::TestCase
+  def setup
+    @family = families(:dylan_family)
+  end
+
+  test "create_default_categories should generate categories if none exist" do
+    @family.accounts.destroy_all
+    @family.transaction_categories.destroy_all
+    assert_difference "Transaction::Category.count", Transaction::Category::DEFAULT_CATEGORIES.size do
+      Transaction::Category.create_default_categories(@family)
+    end
+  end
+
+  test "create_default_categories should raise when there are existing categories" do
+    assert_raises(ArgumentError) do
+      Transaction::Category.create_default_categories(@family)
+    end
+  end
+
+  test "updating name should clear the internal_category field" do
+    category = Transaction::Category.take
+    assert_changes "category.reload.internal_category", to: nil do
+      category.update_attribute(:name, "new name")
+    end
+  end
+
+  test "updating other field than name should not clear the internal_category field" do
+    category = Transaction::Category.take
+    assert_no_changes "category.reload.internal_category" do
+      category.update_attribute(:color, "#000")
+    end
+  end
+end