1 files changed, 136 insertions, 0 deletions
diff --git a/spec/lib/gitlab/analytics/date_filler_spec.rb b/spec/lib/gitlab/analytics/date_filler_spec.rb
new file mode 100644
index 00000000000..3f547f667f2
--- /dev/null
+++ b/spec/lib/gitlab/analytics/date_filler_spec.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+require 'fast_spec_helper'
+
+RSpec.describe Gitlab::Analytics::DateFiller do
+  let(:default_value) { 0 }
+  let(:formatter) { Gitlab::Analytics::DateFiller::DEFAULT_DATE_FORMATTER }
+
+  subject(:filler_result) do
+    described_class.new(data,
+                        from: from,
+                        to: to,
+                        period: period,
+                        default_value: default_value,
+                        date_formatter: formatter).fill.to_a
+  end
+
+  context 'when unknown period is given' do
+    it 'raises error' do
+      input = { 3.days.ago.to_date => 10, Date.today => 5 }
+
+      expect do
+        described_class.new(input, from: 4.days.ago, to: Date.today, period: :unknown).fill
+      end.to raise_error(/Unknown period given/)
+    end
+  end
+
+  context 'when period=:day' do
+    let(:from) { Date.new(2021, 5, 25) }
+    let(:to) { Date.new(2021, 6, 5) }
+    let(:period) { :day }
+
+    let(:expected_result) do
+      {
+        Date.new(2021, 5, 25) => 1,
+        Date.new(2021, 5, 26) => default_value,
+        Date.new(2021, 5, 27) => default_value,
+        Date.new(2021, 5, 28) => default_value,
+        Date.new(2021, 5, 29) => default_value,
+        Date.new(2021, 5, 30) => default_value,
+        Date.new(2021, 5, 31) => default_value,
+        Date.new(2021, 6, 1) => default_value,
+        Date.new(2021, 6, 2) => default_value,
+        Date.new(2021, 6, 3) => 10,
+        Date.new(2021, 6, 4) => default_value,
+        Date.new(2021, 6, 5) => default_value
+      }
+    end
+
+    let(:data) do
+      {
+        Date.new(2021, 6, 3) => 10, # deliberatly not sorted
+        Date.new(2021, 5, 27) => nil,
+        Date.new(2021, 5, 25) => 1
+      }
+    end
+
+    it { is_expected.to eq(expected_result.to_a) }
+
+    context 'when a custom default value is given' do
+      let(:default_value) { 'MISSING' }
+
+      it do
+        is_expected.to eq(expected_result.to_a)
+      end
+    end
+
+    context 'when a custom date formatter is given' do
+      let(:formatter) { -> (date) { date.to_s } }
+
+      it do
+        expected_result.transform_keys!(&:to_s)
+
+        is_expected.to eq(expected_result.to_a)
+      end
+    end
+
+    context 'when the data contains dates outside of the requested period' do
+      before do
+        data[Date.new(2022, 6, 1)] = 5
+      end
+
+      it 'raises error' do
+        expect { filler_result }.to raise_error(/Input contains values which doesn't/)
+      end
+    end
+  end
+
+  context 'when period=:week' do
+    let(:from) { Date.new(2021, 5, 16) }
+    let(:to) { Date.new(2021, 6, 7) }
+    let(:period) { :week }
+    let(:data) do
+      {
+        Date.new(2021, 5, 24) => nil,
+        Date.new(2021, 6, 7) => 10
+      }
+    end
+
+    let(:expected_result) do
+      {
+        Date.new(2021, 5, 10) => 0,
+        Date.new(2021, 5, 17) => 0,
+        Date.new(2021, 5, 24) => 0,
+        Date.new(2021, 5, 31) => 0,
+        Date.new(2021, 6, 7) => 10
+      }
+    end
+
+    it do
+      is_expected.to eq(expected_result.to_a)
+    end
+  end
+
+  context 'when period=:month' do
+    let(:from) { Date.new(2021, 5, 1) }
+    let(:to) { Date.new(2021, 7, 1) }
+    let(:period) { :month }
+    let(:data) do
+      {
+        Date.new(2021, 5, 1) => 100
+      }
+    end
+
+    let(:expected_result) do
+      {
+        Date.new(2021, 5, 1) => 100,
+        Date.new(2021, 6, 1) => 0,
+        Date.new(2021, 7, 1) => 0
+      }
+    end
+
+    it do
+      is_expected.to eq(expected_result.to_a)
+    end
+  end
+end