Change trending hashtags to not disappear instantly after midnight (#11712)

1 files changed, 68 insertions, 0 deletions

diff --git a/spec/models/trending_tags_spec.rb b/spec/models/trending_tags_spec.rb
new file mode 100644
index 000000000..b6122c994
--- /dev/null
+++ b/spec/models/trending_tags_spec.rb
@@ -0,0 +1,68 @@
+require 'rails_helper'
+
+RSpec.describe TrendingTags do
+  describe '.record_use!' do
+    pending
+  end
+
+  describe '.update!' do
+    let!(:at_time) { Time.now.utc }
+    let!(:tag1) { Fabricate(:tag, name: 'Catstodon') }
+    let!(:tag2) { Fabricate(:tag, name: 'DogsOfMastodon') }
+    let!(:tag3) { Fabricate(:tag, name: 'OCs') }
+
+    before do
+      allow(Redis.current).to receive(:pfcount) do |key|
+        case key
+        when "activity:tags:#{tag1.id}:#{(at_time - 1.day).beginning_of_day.to_i}:accounts"
+          2
+        when "activity:tags:#{tag1.id}:#{at_time.beginning_of_day.to_i}:accounts"
+          16
+        when "activity:tags:#{tag2.id}:#{(at_time - 1.day).beginning_of_day.to_i}:accounts"
+          0
+        when "activity:tags:#{tag2.id}:#{at_time.beginning_of_day.to_i}:accounts"
+          4
+        when "activity:tags:#{tag3.id}:#{(at_time - 1.day).beginning_of_day.to_i}:accounts"
+          13
+        end
+      end
+
+      Redis.current.zadd('trending_tags', 0.9, tag3.id)
+      Redis.current.sadd("trending_tags:used:#{at_time.beginning_of_day.to_i}", [tag1.id, tag2.id])
+
+      tag3.update(max_score: 0.9, max_score_at: (at_time - 1.day).beginning_of_day + 12.hours)
+
+      described_class.update!(at_time)
+    end
+
+    it 'calculates and re-calculates scores' do
+      expect(described_class.get(10, filtered: false)).to eq [tag1, tag3]
+    end
+
+    it 'omits hashtags below threshold' do
+      expect(described_class.get(10, filtered: false)).to_not include(tag2)
+    end
+
+    it 'decays scores' do
+      expect(Redis.current.zscore('trending_tags', tag3.id)).to be < 0.9
+    end
+  end
+
+  describe '.trending?' do
+    let(:tag) { Fabricate(:tag) }
+
+    before do
+      10.times { |i| Redis.current.zadd('trending_tags', i + 1, Fabricate(:tag).id) }
+    end
+
+    it 'returns true if the hashtag is within limit' do
+      Redis.current.zadd('trending_tags', 11, tag.id)
+      expect(described_class.trending?(tag)).to be true
+    end
+
+    it 'returns false if the hashtag is outside the limit' do
+      Redis.current.zadd('trending_tags', 0, tag.id)
+      expect(described_class.trending?(tag)).to be false
+    end
+  end
+end