test: add unit tests for LomiClient initialization and sandbox environment

Author: princemuichkine

tests/test_client.py

@@ -0,0 +1,15 @@
+import unittest
+from lomi import LomiClient
+
+class TestLomiClient(unittest.TestCase):
+    def test_init(self):
+        client = LomiClient(api_key="test_key")
+        self.assertEqual(client.api_key, "test_key")
+        self.assertEqual(client.base_url, "https://api.lomi.africa")
+
+    def test_sandbox(self):
+        client = LomiClient(api_key="test_key", environment="test")
+        self.assertEqual(client.base_url, "https://sandbox.api.lomi.africa")
+
+if __name__ == '__main__':
+    unittest.main()