1 files changed, 60 insertions, 0 deletions
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 63a73101c4..4938b6865f 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -1488,4 +1488,64 @@ class BasicsTest < ActiveRecord::TestCase
   ensure
     ActiveRecord::Base.protected_environments = previous_protected_environments
   end
+
+  test "creating a record raises if preventing writes" do
+    error = assert_raises ActiveRecord::ReadOnlyError do
+      ActiveRecord::Base.connection.while_preventing_writes do
+        Bird.create! name: "Bluejay"
+      end
+    end
+
+    assert_match %r/\AWrite query attempted while in readonly mode: INSERT /, error.message
+  end
+
+  test "updating a record raises if preventing writes" do
+    bird = Bird.create! name: "Bluejay"
+
+    error = assert_raises ActiveRecord::ReadOnlyError do
+      ActiveRecord::Base.connection.while_preventing_writes do
+        bird.update! name: "Robin"
+      end
+    end
+
+    assert_match %r/\AWrite query attempted while in readonly mode: UPDATE /, error.message
+  end
+
+  test "deleting a record raises if preventing writes" do
+    bird = Bird.create! name: "Bluejay"
+
+    error = assert_raises ActiveRecord::ReadOnlyError do
+      ActiveRecord::Base.connection.while_preventing_writes do
+        bird.destroy!
+      end
+    end
+
+    assert_match %r/\AWrite query attempted while in readonly mode: DELETE /, error.message
+  end
+
+  test "selecting a record does not raise if preventing writes" do
+    bird = Bird.create! name: "Bluejay"
+
+    ActiveRecord::Base.connection.while_preventing_writes do
+      assert_equal bird, Bird.where(name: "Bluejay").first
+    end
+  end
+
+  test "an explain query does not raise if preventing writes" do
+    Bird.create!(name: "Bluejay")
+
+    ActiveRecord::Base.connection.while_preventing_writes do
+      assert_queries(2) { Bird.where(name: "Bluejay").explain }
+    end
+  end
+
+  test "an empty transaction does not raise if preventing writes" do
+    ActiveRecord::Base.connection.while_preventing_writes do
+      assert_queries(2, ignore_none: true) do
+        Bird.transaction do
+          ActiveRecord::Base.connection.materialize_transactions
+        end
+      end
+    end
+  end
 end