add test

tests/test_global_header.py

@@ -0,0 +1,30 @@
+import httpretty
+import requests as requests
+
+import shippo
+
+BASE_URL = "http://localhost:9500"
+
+
+class TestGlobalHeader:
+
+    def request_callback(self, request, uri, response_headers):
+        assert request.headers.get('header_param') == "value"
+        return [200, {}, '{}']
+
+    @httpretty.activate(allow_net_connect=False)
+    def test_local_header(self):
+        httpretty.register_uri(httpretty.GET, f"{BASE_URL}/example", body=self.request_callback)
+
+        api = shippo.Shippo(server_url=BASE_URL)
+        api.example(header_param="value")
+
+    @httpretty.activate(allow_net_connect=False)
+    def test_global_header(self):
+        httpretty.register_uri(httpretty.GET, f"{BASE_URL}/example", body=self.request_callback)
+
+        http_client = requests.Session()
+        http_client.headers.update({'header_param': 'value'})
+        api = shippo.Shippo(server_url=BASE_URL, client=http_client)
+
+        api.example()