3 files changed, 19 insertions, 26 deletions
diff --git a/activerecord/test/cases/locking_test.rb b/activerecord/test/cases/locking_test.rb
index 6791d50940..e857180bd1 100644
--- a/activerecord/test/cases/locking_test.rb
+++ b/activerecord/test/cases/locking_test.rb
@@ -611,14 +611,12 @@ unless in_memory_db?
       end
     end
 
-    if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
-      def test_no_locks_no_wait
-        first, second = duel { Person.find 1 }
-        assert first.end > second.end
-      end
-
-      private
+    def test_no_locks_no_wait
+      first, second = duel { Person.find 1 }
+      assert first.end > second.end
+    end
 
+    private
       def duel(zzz = 5)
         t0, t1, t2, t3 = nil, nil, nil, nil
 
@@ -646,6 +644,5 @@ unless in_memory_db?
         assert t3 > t2
         [t0.to_f..t1.to_f, t2.to_f..t3.to_f]
       end
-    end
   end
 end
diff --git a/activerecord/test/cases/transaction_isolation_test.rb b/activerecord/test/cases/transaction_isolation_test.rb
index b1ebccdcc3..eaafd13360 100644
--- a/activerecord/test/cases/transaction_isolation_test.rb
+++ b/activerecord/test/cases/transaction_isolation_test.rb
@@ -15,9 +15,7 @@ unless ActiveRecord::Base.connection.supports_transaction_isolation?
       end
     end
   end
-end
-
-if ActiveRecord::Base.connection.supports_transaction_isolation?
+else
   class TransactionIsolationTest < ActiveRecord::TestCase
     self.use_transactional_tests = false
 
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
index 7fd125ab74..5c8ae4d3cb 100644
--- a/activerecord/test/cases/transactions_test.rb
+++ b/activerecord/test/cases/transactions_test.rb
@@ -954,27 +954,25 @@ class TransactionsWithTransactionalFixturesTest < ActiveRecord::TestCase
   end
 end if Topic.connection.supports_savepoints?
 
-if current_adapter?(:PostgreSQLAdapter)
+if ActiveRecord::Base.connection.supports_transaction_isolation?
   class ConcurrentTransactionTest < TransactionTest
     # This will cause transactions to overlap and fail unless they are performed on
     # separate database connections.
-    unless in_memory_db?
-      def test_transaction_per_thread
-        threads = 3.times.map do
-          Thread.new do
-            Topic.transaction do
-              topic = Topic.find(1)
-              topic.approved = !topic.approved?
-              assert topic.save!
-              topic.approved = !topic.approved?
-              assert topic.save!
-            end
-            Topic.connection.close
+    def test_transaction_per_thread
+      threads = 3.times.map do
+        Thread.new do
+          Topic.transaction do
+            topic = Topic.find(1)
+            topic.approved = !topic.approved?
+            assert topic.save!
+            topic.approved = !topic.approved?
+            assert topic.save!
           end
+          Topic.connection.close
         end
-
-        threads.each(&:join)
       end
+
+      threads.each(&:join)
     end
 
     # Test for dirty reads among simultaneous transactions.