[O] Separate register function

src/test/kotlin/ext/TestExt.kt

@@ -1,5 +1,7 @@
 package ext
 
+import io.ktor.client.request.*
+import io.ktor.client.statement.*
 import kotlin.random.Random
 import kotlin.random.nextInt
 
@@ -17,4 +19,16 @@ catch (e: Exception) {
 }
 
 fun String.jsonMap(): Map<String, Any?> = json()
-fun String.jsonArray(): List<Map<String, Any?>> = json()
+fun String.jsonArray(): List<Map<String, Any?>> = json()
+
+suspend fun registerUser(): Long {
+    val resp = HTTP.post(HOST.ensureEndingSlash() + "api/v2/frontier/register-card") {
+        parameter("ftk", FTK)
+        parameter("accessCode", ACCESS_CODE)
+    }.bodyAsText()
+
+    val userId = (resp.jsonMap()["id"] as Number).toLong()
+    println("User ID: $userId")
+
+    return userId
+}