diff --git a/tests/aux_tests/test_find_unique_phonemes.py b/tests/aux_tests/test_find_unique_phonemes.py
new file mode 100644
index 00000000..33fad9ba
--- /dev/null
+++ b/tests/aux_tests/test_find_unique_phonemes.py
@@ -0,0 +1,84 @@
+import os
+import unittest
+
+import torch
+
+from tests import get_tests_output_path, run_cli
+from TTS.config.shared_configs import BaseDatasetConfig
+from TTS.tts.configs.vits_config import VitsConfig
+
+torch.manual_seed(1)
+
+config_path = os.path.join(get_tests_output_path(), "test_model_config.json")
+
+dataset_config_en = BaseDatasetConfig(
+    name="ljspeech",
+    meta_file_train="metadata.csv",
+    meta_file_val="metadata.csv",
+    path="tests/data/ljspeech",
+    language="en",
+)
+
+dataset_config_pt = BaseDatasetConfig(
+    name="ljspeech",
+    meta_file_train="metadata.csv",
+    meta_file_val="metadata.csv",
+    path="tests/data/ljspeech",
+    language="pt-br",
+)
+
+# pylint: disable=protected-access
+class TestFindUniquePhonemes(unittest.TestCase):
+    @staticmethod
+    def test_espeak_phonemes():
+       # prepare the config
+        config = VitsConfig(
+            batch_size=2,
+            eval_batch_size=2,
+            num_loader_workers=0,
+            num_eval_loader_workers=0,
+            text_cleaner="english_cleaners",
+            use_phonemes=True,
+            use_espeak_phonemes=True,
+            phoneme_language="en-us",
+            phoneme_cache_path="tests/data/ljspeech/phoneme_cache/",
+            run_eval=True,
+            test_delay_epochs=-1,
+            epochs=1,
+            print_step=1,
+            print_eval=True,
+            datasets=[dataset_config_en, dataset_config_pt],
+        )
+        config.save_json(config_path)
+
+        # run test
+        run_cli(
+            f'CUDA_VISIBLE_DEVICES="" python TTS/bin/find_unique_phonemes.py --config_path "{config_path}"'
+        )
+
+    @staticmethod
+    def test_no_espeak_phonemes():
+        # prepare the config
+        config = VitsConfig(
+            batch_size=2,
+            eval_batch_size=2,
+            num_loader_workers=0,
+            num_eval_loader_workers=0,
+            text_cleaner="english_cleaners",
+            use_phonemes=True,
+            use_espeak_phonemes=False,
+            phoneme_language="en-us",
+            phoneme_cache_path="tests/data/ljspeech/phoneme_cache/",
+            run_eval=True,
+            test_delay_epochs=-1,
+            epochs=1,
+            print_step=1,
+            print_eval=True,
+            datasets=[dataset_config_en, dataset_config_pt],
+        )
+        config.save_json(config_path)
+
+        # run test
+        run_cli(
+            f'CUDA_VISIBLE_DEVICES="" python TTS/bin/find_unique_phonemes.py --config_path "{config_path}"'
+        )