copy from https://github.com/SOR2171/Springboot4-Vue3_Demo

src/test/kotlin/ServerTest.kt

@@ -1,18 +1,23 @@
 package io.github.sor2171
 
-import io.ktor.client.request.get
-import io.ktor.http.HttpStatusCode
-import io.ktor.server.testing.testApplication
+import io.ktor.client.request.*
+import io.ktor.client.statement.*
+import io.ktor.http.*
+import io.ktor.server.response.*
+import io.ktor.server.routing.*
+import io.ktor.server.testing.*
 import kotlin.test.*
 
 class ServerTest {
-
     @Test
-    fun `test root endpoint`() = testApplication {
-        // loads default configuration
-        configure()
-        // verify server root returns 200
-        assertEquals(HttpStatusCode.OK, client.get("/").status)
+    fun `test basic test route`() = testApplication {
+        routing {
+            get("/api/test/hello") {
+                call.respondText("Hello Kotlin WebFlux!")
+            }
+        }
+        val response = client.get("/api/test/hello")
+        assertEquals(HttpStatusCode.OK, response.status)
+        assertEquals("Hello Kotlin WebFlux!", response.bodyAsText())
     }
-
 }