1 files changed, 99 insertions, 0 deletions
diff --git a/spec/services/cohorts_service_spec.rb b/spec/services/cohorts_service_spec.rb
new file mode 100644
index 00000000000..77595d7ba2d
--- /dev/null
+++ b/spec/services/cohorts_service_spec.rb
@@ -0,0 +1,99 @@
+require 'spec_helper'
+
+describe CohortsService do
+  describe '#execute' do
+    def month_start(months_ago)
+      months_ago.months.ago.beginning_of_month.to_date
+    end
+
+    # In the interests of speed and clarity, this example has minimal data.
+    it 'returns a list of user cohorts' do
+      6.times do |months_ago|
+        months_ago_time = (months_ago * 2).months.ago
+
+        create(:user, created_at: months_ago_time, last_activity_on: Time.now)
+        create(:user, created_at: months_ago_time, last_activity_on: months_ago_time)
+      end
+
+      create(:user) # this user is inactive and belongs to the current month
+
+      expected_cohorts = [
+        {
+          registration_month: month_start(11),
+          activity_months: Array.new(12) { { total: 0, percentage: 0 } },
+          total: 0,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(10),
+          activity_months: [{ total: 2, percentage: 100 }] + Array.new(10) { { total: 1, percentage: 50 } },
+          total: 2,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(9),
+          activity_months: Array.new(10) { { total: 0, percentage: 0 } },
+          total: 0,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(8),
+          activity_months: [{ total: 2, percentage: 100 }] + Array.new(8) { { total: 1, percentage: 50 } },
+          total: 2,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(7),
+          activity_months: Array.new(8) { { total: 0, percentage: 0 } },
+          total: 0,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(6),
+          activity_months: [{ total: 2, percentage: 100 }] + Array.new(6) { { total: 1, percentage: 50 } },
+          total: 2,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(5),
+          activity_months: Array.new(6) { { total: 0, percentage: 0 } },
+          total: 0,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(4),
+          activity_months: [{ total: 2, percentage: 100 }] + Array.new(4) { { total: 1, percentage: 50 } },
+          total: 2,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(3),
+          activity_months: Array.new(4) { { total: 0, percentage: 0 } },
+          total: 0,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(2),
+          activity_months: [{ total: 2, percentage: 100 }] + Array.new(2) { { total: 1, percentage: 50 } },
+          total: 2,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(1),
+          activity_months: Array.new(2) { { total: 0, percentage: 0 } },
+          total: 0,
+          inactive: 0
+        },
+        {
+          registration_month: month_start(0),
+          activity_months: [{ total: 2, percentage: 100 }],
+          total: 2,
+          inactive: 1
+        }
+      ]
+
+      expect(described_class.new.execute).to eq(months_included: 12,
+                                                cohorts: expected_cohorts)
+    end
+  end
+end