Re-use issue/MR counts for the pagination systemmr-index-page-performance

This changes the issue and MR index pages so the pagination system
re-uses the output of the COUNT(*) query used to calculate the number of
rows per state (opened, closed, etc). This removes the need for an
additional COUNT(*) on both pages.

1 files changed, 37 insertions, 0 deletions

diff --git a/spec/lib/gitlab/issuables_count_for_state_spec.rb b/spec/lib/gitlab/issuables_count_for_state_spec.rb
new file mode 100644
index 00000000000..c262fdfcb61
--- /dev/null
+++ b/spec/lib/gitlab/issuables_count_for_state_spec.rb
@@ -0,0 +1,37 @@
+require 'spec_helper'
+
+describe Gitlab::IssuablesCountForState do
+  let(:finder) do
+    double(:finder, count_by_state: { opened: 2, closed: 1 })
+  end
+
+  let(:counter) { described_class.new(finder) }
+
+  describe '#for_state_or_opened' do
+    it 'returns the number of issuables for the given state' do
+      expect(counter.for_state_or_opened(:closed)).to eq(1)
+    end
+
+    it 'returns the number of open issuables when no state is given' do
+      expect(counter.for_state_or_opened).to eq(2)
+    end
+
+    it 'returns the number of open issuables when a nil value is given' do
+      expect(counter.for_state_or_opened(nil)).to eq(2)
+    end
+  end
+
+  describe '#[]' do
+    it 'returns the number of issuables for the given state' do
+      expect(counter[:closed]).to eq(1)
+    end
+
+    it 'casts valid states from Strings to Symbols' do
+      expect(counter['closed']).to eq(1)
+    end
+
+    it 'returns 0 when using an invalid state name as a String' do
+      expect(counter['kittens']).to be_zero
+    end
+  end
+end