more tests / examples for recommender

spec/models/domain/fa/user_factor_spec.rb

@@ -1,7 +1,7 @@
 require "rails_helper"
 
 describe Domain::Fa::UserFactor do
-  it "works" do
+  it "provides an example of how to use disco / neighbor" do
     # a few clusters of users, followed by a few others
     cluster1 = 10.times.map do |i|
       SpecUtil.create_domain_fa_user(name: "cluster-1-#{i}")
@@ -11,10 +11,10 @@ describe Domain::Fa::UserFactor do
       SpecUtil.create_domain_fa_user(name: "cluster-2-#{i}")
     end
 
-    cluster1_ids = cluster1.map(&:name)
-    cluster2_ids = cluster2.map(&:name)
+    cluster1_ids = Set.new cluster1.map(&:name)
+    cluster2_ids = Set.new cluster2.map(&:name)
 
-    follower1, follower2, follower3 = 3.times.map do |i|
+    follower1, follower2, follower3, follower4 = 4.times.map do |i|
       SpecUtil.create_domain_fa_user(name: "follower-#{i + 1}")
     end
 
@@ -33,6 +33,11 @@ describe Domain::Fa::UserFactor do
       Domain::Fa::Follow.create!(follower: follower3, followed: user)
     end
 
+    # follower4 follows a few in cluster1
+    cluster1[0...2].each do |user|
+      Domain::Fa::Follow.create!(follower: follower4, followed: user)
+    end
+
     # calculate the recommender
     recommender = Disco::Recommender.new(
       factors: Domain::Fa::UserFactor.neighbor_attributes[:factors][:dimensions],
@@ -49,13 +54,19 @@ describe Domain::Fa::UserFactor do
 
     # cluster1 should all be similar to each other
     cluster1.each do |user|
-      ids = Set.new(recommender.similar_items(user.name, count: 9))
-      expected = Set.new(cluster1_ids)
-      actual = Set.new(ids.map do |id|
-        id[:item_id]
+      similar_items = Set.new(recommender.similar_items(user.name, count: 9))
+      similar_item_ids = Set.new(similar_items.map do |item|
+        item[:item_id]
       end)
 
-      assert expected.superset?(actual), ids
+      assert cluster1_ids.superset?(similar_item_ids), similar_items
     end
+
+    # follower4's follow recommendations should be other users in cluster1
+    follower4_recs = Set.new(recommender.user_recs(follower4.name))
+    follower4_rec_ids = Set.new(follower4_recs.map do |item|
+      item[:item_id]
+    end)
+    assert cluster1_ids.superset?(follower4_rec_ids), follower4_recs
   end
 end