MONGOID-5079 clear has_many association locally after destroy_all (#5278)

* MONGOID-5079 has_many association is not cleared after destroy_all

* MONGOID-5079 fix tests

* MONGOID-5079 add HABTM tests

Author: neilshweky

lib/mongoid/association/referenced/has_many/proxy.rb

@@ -472,8 +472,8 @@ def remove_all(conditions = nil, method = :delete_all)
             selector = conditions || {}
             removed = klass.send(method, selector.merge!(criteria.selector))
             _target.delete_if do |doc|
-              if doc._matches?(selector)
-                unbind_one(doc) and true
+              doc._matches?(selector).tap do |b|
+                unbind_one(doc) if b
               end
             end
             removed

spec/mongoid/association/referenced/has_and_belongs_to_many/proxy_spec.rb

@@ -2395,6 +2395,10 @@
           it "removes the ids from the foreign key" do
             expect(person.preference_ids).to eq([ preference_two.id ])
           end
+
+          it "sets the association locally" do
+            expect(person.preferences).to eq([preference_two])
+          end
         end
 
         context "when conditions are not provided" do
@@ -2421,6 +2425,10 @@
           it "returns the number of documents deleted" do
             expect(deleted).to eq(2)
           end
+
+          it "sets the association locally" do
+            expect(person.preferences).to eq([])
+          end
         end
       end
     end

spec/mongoid/association/referenced/has_many/proxy_spec.rb

@@ -2239,10 +2239,8 @@
             Person.create!(username: 'durran')
           end
 
-          before do
-            person.posts.create!(title: "Testing")
-            person.posts.create!(title: "Test")
-          end
+          let!(:post1) { person.posts.create!(title: "Testing") }
+          let!(:post2) { person.posts.create!(title: "Test") }
 
           it "removes the correct posts" do
             person.posts.send(method, { title: "Testing" })
@@ -2258,6 +2256,11 @@
           it "returns the number of documents deleted" do
             expect(person.posts.send(method, { title: "Testing" })).to eq(1)
           end
+
+          it "sets the association locally" do
+            person.posts.send(method, { title: "Testing" })
+            expect(person.posts).to eq([post2])
+          end
         end
 
         context "when conditions are not provided" do
@@ -2284,6 +2287,11 @@
           it "returns the number of documents deleted" do
             expect(person.posts.send(method)).to eq(2)
           end
+
+          it "sets the association locally" do
+            person.posts.send(method)
+            expect(person.posts).to eq([])
+          end
         end
       end
 
@@ -2295,10 +2303,8 @@
             Movie.create!(title: "Bladerunner")
           end
 
-          before do
-            movie.ratings.create!(value: 1)
-            movie.ratings.create!(value: 2)
-          end
+          let!(:rating1) { movie.ratings.create!(value: 1) }
+          let!(:rating2) { movie.ratings.create!(value: 2) }
 
           it "removes the correct ratings" do
             movie.ratings.send(method, { value: 1 })
@@ -2313,6 +2319,11 @@
           it "returns the number of documents deleted" do
             expect(movie.ratings.send(method, { value: 1 })).to eq(1)
           end
+
+          it "sets the association locally" do
+            movie.ratings.send(method, { value: 1 })
+            expect(movie.ratings).to eq([rating2])
+          end
         end
 
         context "when conditions are not provided" do
@@ -2339,6 +2350,11 @@
           it "returns the number of documents deleted" do
             expect(movie.ratings.send(method)).to eq(2)
           end
+
+          it "sets the association locally" do
+            movie.ratings.send(method)
+            expect(movie.ratings).to eq([])
+          end
         end
       end
     end