Make columns of user and ordergroup lists sortable

This commit implements the sort functionality for the user lists (by name, email, last_activity) and ordergroup lists (by name).
It is a first attempt addressing issue #560.

spec/models/user_spec.rb

@@ -78,4 +78,122 @@ describe User do
 
     it 'default admin role' do expect(user.role_admin?).to be_truthy end
   end
+
+  describe 'sort correctly' do
+    it 'by nick' do
+      user_b = create :user, nick: 'bbb'
+      user_a = create :user, nick: 'aaa'
+      user_c = create :user, nick: 'ccc'
+
+      expect(User.sort_by_param('nick')).to eq([user_a, user_b, user_c])
+    end
+
+    it 'reverse by nick' do
+      user_b = create :user, nick: 'bbb'
+      user_a = create :user, nick: 'aaa'
+      user_c = create :user, nick: 'ccc'
+
+      expect(User.sort_by_param('nick_reverse')).to eq([user_c, user_b, user_a])
+    end
+
+    it 'by name' do
+      user_b = create :user, first_name: 'aaa', last_name: 'bbb'
+      user_a = create :user, first_name: 'aaa', last_name: 'aaa'
+      user_c = create :user, first_name: 'ccc', last_name: 'aaa'
+
+      expect(User.sort_by_param('name')).to eq([user_a, user_b, user_c])
+    end
+
+    it 'reverse by name' do
+      user_b = create :user, first_name: 'aaa', last_name: 'bbb'
+      user_a = create :user, first_name: 'aaa', last_name: 'aaa'
+      user_c = create :user, first_name: 'ccc', last_name: 'aaa'
+
+      expect(User.sort_by_param('name_reverse')).to eq([user_c, user_b, user_a])
+    end
+
+    it 'by email' do
+      user_b = create :user, email: 'bbb@dummy.com'
+      user_a = create :user, email: 'aaa@dummy.com'
+      user_c = create :user, email: 'ccc@dummy.com'
+
+      expect(User.sort_by_param('email')).to eq([user_a, user_b, user_c])
+    end
+
+    it 'reverse by email' do
+      user_b = create :user, email: 'bbb@dummy.com'
+      user_a = create :user, email: 'aaa@dummy.com'
+      user_c = create :user, email: 'ccc@dummy.com'
+
+      expect(User.sort_by_param('email_reverse')).to eq([user_c, user_b, user_a])
+    end
+
+    it 'by phone' do
+      user_b = create :user, phone: 'bbb'
+      user_a = create :user, phone: 'aaa'
+      user_c = create :user, phone: 'ccc'
+
+      expect(User.sort_by_param('phone')).to eq([user_a, user_b, user_c])
+    end
+
+    it 'reverse by phone' do
+      user_b = create :user, phone: 'bbb'
+      user_a = create :user, phone: 'aaa'
+      user_c = create :user, phone: 'ccc'
+
+      expect(User.sort_by_param('phone_reverse')).to eq([user_c, user_b, user_a])
+    end
+
+    it 'by last_activity' do
+      user_b = create :user, last_activity: 3.days.ago
+      user_a = create :user, last_activity: 5.days.ago
+      user_c = create :user, last_activity: Time.now
+
+      expect(User.sort_by_param('last_activity')).to eq([user_a, user_b, user_c])
+    end
+
+    it 'reverse by last_activity' do
+      user_b = create :user, last_activity: 3.days.ago
+      user_a = create :user, last_activity: 5.days.ago
+      user_c = create :user, last_activity: Time.now
+
+      expect(User.sort_by_param('last_activity_reverse')).to eq([user_c, user_b, user_a])
+    end
+
+    it 'by ordergroup' do
+      user_b = create :user, groups: [create(:workgroup, name: 'a'), create(:ordergroup, name: 'bb')]
+      user_a = create :user, groups: [create(:workgroup, name: 'b'), create(:ordergroup, name: 'aa')]
+      user_c = create :user, groups: [create(:workgroup, name: 'c'), create(:ordergroup, name: 'cc')]
+
+      expect(User.sort_by_param('ordergroup')).to eq([user_a, user_b, user_c])
+    end
+
+    it 'reverse by ordergroup' do
+      user_b = create :user, groups: [create(:workgroup, name: 'a'), create(:ordergroup, name: 'bb')]
+      user_a = create :user, groups: [create(:workgroup, name: 'b'), create(:ordergroup, name: 'aa')]
+      user_c = create :user, groups: [create(:workgroup, name: 'c'), create(:ordergroup, name: 'cc')]
+
+      expect(User.sort_by_param('ordergroup_reverse')).to eq([user_c, user_b, user_a])
+    end
+
+    it 'and users are only listed once' do
+      create :user
+
+      expect(User.sort_by_param('ordergroup').size).to eq(1)
+    end
+
+    it 'and users belonging to a workgroup are only listed once' do
+      create :admin
+
+      expect(User.sort_by_param('ordergroup').size).to eq(1)
+    end
+
+    it 'and users belonging to 2 ordergroups are only listed once' do
+      user = create :user
+      create :ordergroup, user_ids: [user.id]
+      create :ordergroup, user_ids: [user.id]
+
+      expect(User.sort_by_param('ordergroup').size).to eq(1)
+    end
+  end
 end