revert date changes in different specs and add some additional specs

spec/domain/invoices/sac_memberships/member_spec.rb

@@ -39,13 +39,23 @@
     let(:person) { context.people_with_membership_years.find(people(:mitglied).id) }
 
     it "counts years correctly" do
-      roles(:mitglied).update_column(:created_at, "2015-01-20")
-      expect(subject.membership_years).to eq(9)
+      roles(:mitglied).update_column(:created_at, "2015-01-01")
+      expect(subject.membership_years).to eq(8)
     end
 
     it "is off by one in first year" do
       roles(:mitglied).update_column(:created_at, date)
-      expect(subject.membership_years).to eq(2)
+      expect(subject.membership_years).to eq(0)
+    end
+
+    it "counts years correctly in second year" do
+      roles(:mitglied).update_column(:created_at, "2023-01-01")
+      expect(subject.membership_years).to eq(0)
+    end
+
+    it "counts years correctly in third year" do
+      roles(:mitglied).update_column(:created_at, "2022-01-01")
+      expect(subject.membership_years).to eq(1)
     end
   end
 

spec/domain/invoices/sac_memberships/position_generator_spec.rb

@@ -606,7 +606,7 @@
 
     context "last year without reduction" do
       before do
-        roles(:mitglied).update!(created_at: Date.new(date.year - 24, 12, 31))
+        roles(:mitglied).update!(created_at: Date.new(date.year - 24, 1, 1))
       end
 
       it "generates positions without reduction" do