Add specs.

app/models/milestone.rb

@@ -111,6 +111,7 @@ class Milestone < ActiveRecord::Base
   end
 
   def percent_time_used
+    return 0 unless due_date
     return 100 if expired?
 
     duration = ((created_at - due_date.to_datetime) / 1.day)

features/project/milestone.feature

+Feature: Project Milestone
+  Background:
+    Given I sign in as a user
+    And I own project "Shop"
+    And project "Shop" has labels: "bug", "feature", "enhancement"
+    And project "Shop" has milestone "v2.2"
+    And milestone has issue "Bugfix1" with labels: "bug", "feature"
+    And milestone has issue "Bugfix2" with labels: "bug", "enhancement"
+
+
+  @javascript
+  Scenario: Listing issues from issues tab
+    Given I visit project "Shop" milestones page
+    And I click link "v2.2"
+    Then I should see the labels "bug", "enhancement" and "feature"
+
+  @javascript
+  Scenario: Listing labels from labels tab
+    Given I visit project "Shop" milestones page
+    And I click link "v2.2"
+    And I click link "Labels"
+    Then I should see the list of labels
+    And I should see the labels "bug", "enhancement" and "feature"

features/steps/project/project_milestone.rb

+class Spinach::Features::ProjectMilestone < Spinach::FeatureSteps
+  include SharedAuthentication
+  include SharedProject
+  include SharedPaths
+
+  step 'milestone has issue "Bugfix1" with labels: "bug", "feature"' do
+    project = Project.find_by(name: "Shop")
+    milestone = project.milestones.find_by(title: 'v2.2')
+    issue = create(:issue, title: "Bugfix1", project: project, milestone: milestone)
+    issue.labels << project.labels.find_by(title: 'bug')
+    issue.labels << project.labels.find_by(title: 'feature')
+  end
+
+  step 'milestone has issue "Bugfix2" with labels: "bug", "enhancement"' do
+    project = Project.find_by(name: "Shop")
+    milestone = project.milestones.find_by(title: 'v2.2')
+    issue = create(:issue, title: "Bugfix2", project: project, milestone: milestone)
+    issue.labels << project.labels.find_by(title: 'bug')
+    issue.labels << project.labels.find_by(title: 'enhancement')
+  end
+
+  step 'project "Shop" has milestone "v2.2"' do
+    project = Project.find_by(name: "Shop")
+    milestone = create(:milestone,
+                       title: "v2.2",
+                       project: project,
+                       description: "# Description header"
+                      )
+    3.times { create(:issue, project: project, milestone: milestone) }
+  end
+
+  step 'I should see the list of labels' do
+    expect(page).to have_selector('ul.manage-labels-list')
+  end
+
+  step 'I should see the labels "bug", "enhancement" and "feature"' do
+    page.within('#tab-issues') do
+      expect(page).to have_content 'bug'
+      expect(page).to have_content 'enhancement'
+      expect(page).to have_content 'feature'
+    end
+  end
+
+  step 'I click link "v2.2"' do
+    click_link "v2.2"
+  end
+
+  step 'I click link "Labels"' do
+    page.within('.nav-links') do
+      page.find(:xpath, "//a[@href='#tab-labels']").click
+    end
+  end
+end