1 files changed, 52 insertions, 0 deletions
diff --git a/activerecord/test/cases/relation_test.rb b/activerecord/test/cases/relation_test.rb
index 68161f6a84..00a7b3841f 100644
--- a/activerecord/test/cases/relation_test.rb
+++ b/activerecord/test/cases/relation_test.rb
@@ -307,6 +307,58 @@ module ActiveRecord
       assert_equal 3, ratings.count
     end
 
+    def test_relation_with_annotation_includes_comment_in_to_sql
+      post_with_annotation = Post.where(id: 1).annotate("foo")
+      assert_match %r{= 1 /\* foo \*/}, post_with_annotation.to_sql
+    end
+
+    def test_relation_with_annotation_includes_comment_in_sql
+      post_with_annotation = Post.where(id: 1).annotate("foo")
+      assert_sql(%r{/\* foo \*/}) do
+        assert post_with_annotation.first, "record should be found"
+      end
+    end
+
+    def test_relation_with_annotation_chains_sql_comments
+      post_with_annotation = Post.where(id: 1).annotate("foo").annotate("bar")
+      assert_sql(%r{/\* foo \*/ /\* bar \*/}) do
+        assert post_with_annotation.first, "record should be found"
+      end
+    end
+
+    def test_relation_with_annotation_filters_sql_comment_delimiters
+      post_with_annotation = Post.where(id: 1).annotate("**//foo//**")
+      assert_match %r{= 1 /\* foo \*/}, post_with_annotation.to_sql
+    end
+
+    def test_relation_with_annotation_includes_comment_in_count_query
+      post_with_annotation = Post.annotate("foo")
+      all_count = Post.all.to_a.count
+      assert_sql(%r{/\* foo \*/}) do
+        assert_equal all_count, post_with_annotation.count
+      end
+    end
+
+    def test_relation_without_annotation_does_not_include_an_empty_comment
+      log = capture_sql do
+        Post.where(id: 1).first
+      end
+
+      assert_not_predicate log, :empty?
+      assert_predicate log.select { |query| query.match?(%r{/\*}) }, :empty?
+    end
+
+    def test_relation_with_optimizer_hints_filters_sql_comment_delimiters
+      post_with_hint = Post.where(id: 1).optimizer_hints("**//BADHINT//**")
+      assert_match %r{BADHINT}, post_with_hint.to_sql
+      assert_no_match %r{\*/BADHINT}, post_with_hint.to_sql
+      assert_no_match %r{\*//BADHINT}, post_with_hint.to_sql
+      assert_no_match %r{BADHINT/\*}, post_with_hint.to_sql
+      assert_no_match %r{BADHINT//\*}, post_with_hint.to_sql
+      post_with_hint = Post.where(id: 1).optimizer_hints("/*+ BADHINT */")
+      assert_match %r{/\*\+ BADHINT \*/}, post_with_hint.to_sql
+    end
+
     class EnsureRoundTripTypeCasting < ActiveRecord::Type::Value
       def type
         :string