test(classes_test.py): add initial tests

tests/classes_test.py

@@ -0,0 +1,14 @@
+from pyplayht.classes import Client
+
+
+def test_client():
+    client = Client()
+    # check for available methods
+    assert hasattr(client, "get_voices") and callable(client.get_voices)
+    assert hasattr(client, "new_conversion_job") and callable(
+        client.new_conversion_job,
+    )
+    assert hasattr(client, "get_coversion_job_status") and callable(
+        client.get_coversion_job_status,
+    )
+    assert hasattr(client, "download_file") and callable(client.download_file)