Add test that reproduces lazy cache invalidation bug

test/helpers/active_record_objects.rb

@@ -45,6 +45,8 @@ def teardown_models
     Object.send(:remove_const, 'Deeply')
     Object.send(:remove_const, 'CustomMasterRecord')
     Object.send(:remove_const, 'CustomChildRecord')
+    Object.send(:remove_const, 'LazyModel')
+    $LOADED_FEATURES.reject! { |feature| feature.include?("test/helpers/lazy_model/") }
     IdentityCache.const_get(:ParentModelExpiration).send(:lazy_hooks).clear
   end
 end

test/helpers/database_connection.rb

@@ -59,7 +59,10 @@ def self.create_tables
     custom_master_records: [[:integer, :master_primary_key], id: false, primary_key: 'master_primary_key'],
     custom_child_records: [
       [:integer, :child_primary_key], [:integer, :master_id], id: false, primary_key: 'child_primary_key'
-    ]
+    ],
+    lazy_as: [[:string, :name]],
+    lazy_bs: [[:string, :name], [:integer, :a_id]],
+    lazy_cs: [[:string, :name], [:integer, :b_id]],
   }
 
   DEFAULT_CONFIG = {

test/helpers/lazy_model/a.rb

@@ -0,0 +1,8 @@
+module LazyModel
+  class A < ActiveRecord::Base
+    self.table_name = "lazy_as"
+    include IdentityCache
+    has_many :bs, class_name: "::LazyModel::B"
+    cache_has_many :bs, embed: true
+  end
+end

test/helpers/lazy_model/b.rb

@@ -0,0 +1,9 @@
+module LazyModel
+  class B < ActiveRecord::Base
+    self.table_name = "lazy_bs"
+    include IdentityCache
+    belongs_to :a, class_name: "::LazyModel::A", inverse_of: :bs
+    has_one :c, class_name: "::LazyModel::C", inverse_of: :b
+    cache_has_one :c
+  end
+end

test/helpers/lazy_model/c.rb

@@ -0,0 +1,7 @@
+module LazyModel
+  class C < ActiveRecord::Base
+    self.table_name = "lazy_cs"
+    include IdentityCache
+    belongs_to :b, class_name: "::LazyModel::B", inverse_of: :c
+  end
+end

test/helpers/models.rb

@@ -88,3 +88,9 @@ class CustomChildRecord < ActiveRecord::Base
   belongs_to :custom_master_record, foreign_key: :master_id
   self.primary_key = 'child_primary_key'
 end
+
+module LazyModel
+  autoload :A, "helpers/lazy_model/a.rb"
+  autoload :B, "helpers/lazy_model/b.rb"
+  autoload :C, "helpers/lazy_model/c.rb"
+end

test/lazy_hook_test.rb

@@ -0,0 +1,44 @@
+require "test_helper"
+
+class LazyHookTest < IdentityCache::TestCase
+  def test_expires_unloaded_lazy_parent_models
+    # Populate cache
+    a = LazyModel::A.create!(name: "Initial A")
+    b = a.bs.create!(name: "Initial B")
+    c = b.create_c!(name: "Initial C")
+
+    ids = {
+      a: a.id,
+      b: b.id,
+      c: c.id,
+    }
+
+    # Warm cache
+    LazyModel::A.fetch(ids[:a]).fetch_bs.first.fetch_c
+
+    # Clear lazyloaded code to simulate code that isn't eager loaded
+    reset_loaded_code
+    LazyModel::C.find(ids[:c]).update!(name: "Updated C")
+
+    refute(lazy_model_loaded?(:A))
+    refute(lazy_model_loaded?(:B))
+
+    queries = count_queries do
+      c = LazyModel::A.fetch(ids[:a]).fetch_bs.first.fetch_c
+      assert_equal("Updated C", c.name)
+    end
+
+    assert_equal(0, queries)
+  end
+
+  private
+
+  def reset_loaded_code
+    teardown_models
+    setup_models
+  end
+
+  def lazy_model_loaded?(name)
+    !LazyModel.autoload?(name)
+  end
+end