feat: add accept!, decline!, and verify! to Invitation

Adds methods for event invitation management:
- accept!(verified:) - confirms attendance with optional pre-verification
- verify! - marks attendance as verified
- decline! - cancels event attendance

Includes unit tests.

Author: mroderick

app/models/invitation.rb

@@ -24,4 +24,16 @@ def coach_spaces?
   def to_param
     token
   end
+
+  def accept!(verified: false)
+    update!(attending: true, verified: verified)
+  end
+
+  def verify!
+    update!(verified: true)
+  end
+
+  def decline!
+    update!(attending: false)
+  end
 end

spec/models/invitation_spec.rb

@@ -12,19 +12,71 @@
     it { is_expected.to validate_inclusion_of(:role).in_array(%w[Student Coach]) }
   end
 
-  context '#student_spaces?' do
+  describe '#student_spaces?' do
     it 'checks if there are any available spaces for students at the event' do
       student_invitation = Fabricate(:invitation)
 
       expect(student_invitation.student_spaces?).to eq(true)
     end
   end
 
-  context '#coach_spaces?' do
+  describe '#coach_spaces?' do
     it 'checks if there are any available spaces for coaches at the event' do
       coach_invitation = Fabricate(:coach_invitation)
 
       expect(coach_invitation.coach_spaces?).to eq(true)
     end
   end
+
+  describe '#accept!' do
+    let(:invitation) { Fabricate(:invitation, attending: false) }
+
+    it 'sets attending to true' do
+      invitation.accept!
+      expect(invitation.reload.attending).to be true
+    end
+
+    it 'does not verify by default' do
+      invitation.accept!
+      expect(invitation.reload.verified).to be false
+    end
+
+    it 'allows immediate verification' do
+      invitation.accept!(verified: true)
+      expect(invitation.reload.verified).to be true
+    end
+
+    it 'raises RecordInvalid on validation failure' do
+      allow(invitation).to receive(:valid?).and_return(false)
+      expect { invitation.accept! }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+  end
+
+  describe '#verify!' do
+    let(:invitation) { Fabricate(:invitation, verified: false) }
+
+    it 'sets verified to true' do
+      invitation.verify!
+      expect(invitation.reload.verified).to be true
+    end
+
+    it 'raises RecordInvalid on validation failure' do
+      allow(invitation).to receive(:valid?).and_return(false)
+      expect { invitation.verify! }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+  end
+
+  describe '#decline!' do
+    let(:invitation) { Fabricate(:invitation, attending: true) }
+
+    it 'sets attending to false' do
+      invitation.decline!
+      expect(invitation.reload.attending).to be false
+    end
+
+    it 'raises RecordInvalid on validation failure' do
+      allow(invitation).to receive(:valid?).and_return(false)
+      expect { invitation.decline! }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+  end
 end