readd dev dependencies for testing

client/package.json

@@ -46,5 +46,11 @@
       "last 1 safari version"
     ]
   },
-  "proxy": "http://server:4000"
+  "proxy": "http://server:4000",
+  "devDependencies": {
+    "@types/supertest": "^2.0.11",
+    "jest": "^27.4.3",
+    "supertest": "^6.1.6",
+    "ts-jest": "^27.0.7"
+  }
 }