5 files changed, 22 insertions, 5 deletions
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index e61deb1080..bffff07089 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -253,7 +253,8 @@ class FixturesTest < ActiveRecord::TestCase
   end
 
   def test_fixtures_are_set_up_with_database_env_variable
-    ENV.stubs(:[]).with("DATABASE_URL").returns("sqlite3:///:memory:")
+    db_url_tmp = ENV['DATABASE_URL']
+    ENV['DATABASE_URL'] = "sqlite3:///:memory:"
     ActiveRecord::Base.stubs(:configurations).returns({})
     test_case = Class.new(ActiveRecord::TestCase) do
       fixtures :accounts
@@ -266,6 +267,8 @@ class FixturesTest < ActiveRecord::TestCase
     result = test_case.new(:test_fixtures).run
 
     assert result.passed?, "Expected #{result.name} to pass:\n#{result}"
+  ensure
+    ENV['DATABASE_URL'] = db_url_tmp
   end
 end
 
diff --git a/activerecord/test/cases/relation/delegation_test.rb b/activerecord/test/cases/relation/delegation_test.rb
index 71ade0bcc2..c171c5e14e 100644
--- a/activerecord/test/cases/relation/delegation_test.rb
+++ b/activerecord/test/cases/relation/delegation_test.rb
@@ -9,10 +9,11 @@ module ActiveRecord
     def assert_responds(target, method)
       assert target.respond_to?(method)
       assert_nothing_raised do
-        case target.to_a.method(method).arity
-        when 0
+        method_arity = target.to_a.method(method).arity
+
+        if method_arity.zero?
           target.send(method)
-        when -1
+        elsif method_arity < 0
           if method == :shuffle!
             target.send(method)
           else
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 03504ce0c7..ec43ded690 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -634,6 +634,11 @@ class RelationTest < ActiveRecord::TestCase
       relation = Author.where(:id => Author.where(:id => david.id))
       assert_equal [david], relation.to_a
     }
+
+    assert_queries(1) {
+      relation = Author.where('id in (?)', Author.where(id: david).select(:id))
+      assert_equal [david], relation.to_a
+    }
   end
 
   def test_find_all_using_where_with_relation_and_alternate_primary_key
diff --git a/activerecord/test/cases/sanitize_test.rb b/activerecord/test/cases/sanitize_test.rb
index 082570c55b..4c0762deca 100644
--- a/activerecord/test/cases/sanitize_test.rb
+++ b/activerecord/test/cases/sanitize_test.rb
@@ -31,4 +31,10 @@ class SanitizeTest < ActiveRecord::TestCase
     assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi\nand\nThumper"])
     assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi\nand\nThumper".mb_chars])
   end
+
+  def test_sanitize_sql_array_handles_relations
+    assert_match(/\(\bselect\b.*?\bwhere\b.*?\)/i,
+      Binary.send(:sanitize_sql_array, ["id in (?)", Binary.where(id: 1)]),
+      "should sanitize `Relation` as subquery")
+  end
 end
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
index 17206ffe99..980981903a 100644
--- a/activerecord/test/cases/transactions_test.rb
+++ b/activerecord/test/cases/transactions_test.rb
@@ -421,7 +421,9 @@ class TransactionTest < ActiveRecord::TestCase
     topic = Topic.new(:title => 'test')
     topic.freeze
     e = assert_raise(RuntimeError) { topic.save }
-    assert_equal "can't modify frozen Hash", e.message
+    assert_match(/frozen/i, e.message) # Not good enough, but we can't do much
+                                       # about it since there is no specific error
+                                       # for frozen objects.
     assert !topic.persisted?, 'not persisted'
     assert_nil topic.id
     assert topic.frozen?, 'not frozen'