feat: finish unit tests.

.rubocop.yml

@@ -9,8 +9,11 @@ AllCops:
     - 'script/**/*'
     - 'support/**/*'
     - 'tmp/**/*'
-    - 'test/**/*'
 
+Metrics/BlockLength:
+  Enabled: true
+  Exclude:
+    - spec/**/*
 ConditionalAssignment:
   Enabled: false
 StringLiterals:

app/models/task.rb

@@ -1,3 +1,14 @@
 class Task < ApplicationRecord
   validates :action, presence: true, uniqueness: true
+  after_validation :update_finished_at, if: :will_save_change_to_done?
+  # only when finished_at attribute is nil
+  def mark_as_done
+    finished_at.nil? ? self.done = true : errors.add(:done, 'This task has already been marked as done')
+  end
+
+  private
+
+  def update_finished_at
+    self.finished_at = DateTime.now
+  end
 end

spec/models/task_spec.rb

@@ -26,4 +26,34 @@
 
     expect(task).not_to be_valid
   end
+  describe "#mark_as_done" do
+    it "marks a task as done" do
+      task = Task.new(valid_attributes)
+      task.mark_as_done
+      expect(task.done).to eq(true)
+    end
+    it "raises an error message when called more than once" do
+      task = Task.new(valid_attributes)
+      task.mark_as_done
+      task.save!
+      expect(task.mark_as_done[0]).to eq("This task has already been marked as done")
+    end
+  end
+  describe '#update_finished_at' do
+    it "sets the finished_at attribute to a Date after the task has been marked" do
+      task = Task.new(valid_attributes)
+      task.mark_as_done
+      task.save
+      expect(task.finished_at.class).to eq(ActiveSupport::TimeWithZone)
+    end
+    it "is a private method" do
+      task = Task.new(valid_attributes)
+      expect(task.private_methods).to include(:update_finished_at)
+    end
+    it "can update the finished_at attribute of a task when called" do
+      task = Task.new(valid_attributes)
+      task.send(:update_finished_at)
+      expect(task.finished_at.class).to eq(ActiveSupport::TimeWithZone)
+    end
+  end
 end