Add TTS tests

tests/test_tts.py

@@ -0,0 +1,10 @@
+from ukrainian_tts.tts import TTS, Voices, Stress
+from io import BytesIO
+
+def test_tts():
+    tts = TTS(use_cuda=False)
+    file = BytesIO()
+    _, text = tts.tts("Привіт", Voices.Dmytro.value, Stress.Dictionary.value, file)
+    file.seek(0)
+    assert text == "Прив+іт"
+    assert file.getbuffer().nbytes > 1000 # check that file was generated