diff --git a/seqio/dataset_providers_test.py b/seqio/dataset_providers_test.py
index 7fbfb162..3ea4a259 100644
--- a/seqio/dataset_providers_test.py
+++ b/seqio/dataset_providers_test.py
@@ -23,6 +23,7 @@
 
 from absl.testing import absltest
 from absl.testing import parameterized
+from google.protobuf import text_format
 import numpy as np
 import pyglove as pg
 from seqio import dataset_providers
diff --git a/seqio/experimental_test.py b/seqio/experimental_test.py
index faecddad..2faabb62 100644
--- a/seqio/experimental_test.py
+++ b/seqio/experimental_test.py
@@ -18,6 +18,7 @@
 from unittest import mock
 
 from absl.testing import absltest
+from google.protobuf import text_format
 from seqio import dataset_providers
 from seqio import experimental
 from seqio import test_utils
diff --git a/seqio/utils_test.py b/seqio/utils_test.py
index c1fe63b1..5daf3f3d 100644
--- a/seqio/utils_test.py
+++ b/seqio/utils_test.py
@@ -20,6 +20,7 @@
 
 from absl.testing import absltest
 from absl.testing import parameterized
+from google.protobuf import text_format
 import numpy as np
 from seqio import test_utils
 from seqio import utils
diff --git a/seqio/vocabularies_test.py b/seqio/vocabularies_test.py
index edd10f2c..86a84d98 100644
--- a/seqio/vocabularies_test.py
+++ b/seqio/vocabularies_test.py
@@ -16,6 +16,7 @@
 
 from absl.testing import absltest
 from absl.testing import parameterized
+from google.protobuf import text_format
 import numpy as np
 from seqio import test_utils
 from seqio import vocabularies