Check Shift destroy also destroy only associated OfficerAssigments

spec/models/poll/shift_spec.rb

@@ -28,7 +28,7 @@ describe :shift do
 
   describe "officer_assignments" do
 
-    it "should create corresponding officer_assignments" do
+    it "should create and destroy corresponding officer_assignments" do
       poll1 = create(:poll)
       poll2 = create(:poll)
       poll3 = create(:poll)
@@ -39,11 +39,9 @@ describe :shift do
       booth_assignment1 = create(:poll_booth_assignment, poll: poll1, booth: booth)
       booth_assignment2 = create(:poll_booth_assignment, poll: poll2, booth: booth)
 
-      shift = create(:poll_shift, booth: booth, officer: officer, date: Date.current)
+      expect { create(:poll_shift, booth: booth, officer: officer, date: Date.current) }.to change {Poll::OfficerAssignment.all.count}.by(2)
 
       officer_assignments = Poll::OfficerAssignment.all
-      expect(officer_assignments.count).to eq(2)
-
       oa1 = officer_assignments.first
       oa2 = officer_assignments.second
 
@@ -56,6 +54,10 @@ describe :shift do
       expect(oa2.date).to eq(Date.current)
       expect(oa2.booth_assignment).to eq(booth_assignment2)
       expect(oa2.final).to be_falsey
+
+      create(:poll_officer_assignment, officer: officer, booth_assignment: booth_assignment1, date: Date.tomorrow)
+
+      expect { Poll::Shift.last.destroy }.to change {Poll::OfficerAssignment.all.count}.by(-2)
     end
 
     it "should create final officer_assignments" do