Revert "TimeStream Query is no longer accepting new customers, remove E2E test"

This reverts commit 66ec97b.

Author: lauzadis

services/timestreamquery/e2eTest/src/EndpointDiscoveryTest.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package aws.sdk.kotlin.services.timestreamquery
+
+import aws.sdk.kotlin.services.timestreamquery.model.DescribeEndpointsResponse
+import aws.sdk.kotlin.services.timestreamquery.model.ListScheduledQueriesResponse
+import aws.smithy.kotlin.runtime.client.ResponseInterceptorContext
+import aws.smithy.kotlin.runtime.client.operationName
+import aws.smithy.kotlin.runtime.http.interceptors.HttpInterceptor
+import aws.smithy.kotlin.runtime.http.request.HttpRequest
+import aws.smithy.kotlin.runtime.http.response.HttpResponse
+import kotlinx.coroutines.runBlocking
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNotNull
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestInstance
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class EndpointDiscoveryTest {
+    @Test
+    fun testEndpointDiscovery() = runBlocking {
+        val operationLog = mutableListOf<String>()
+        var discoveredHost: String? = null
+
+        val interceptor = object : HttpInterceptor {
+            override fun readAfterExecution(
+                context: ResponseInterceptorContext<Any, Any, HttpRequest?, HttpResponse?>,
+            ) {
+                operationLog += context.executionContext.operationName!!
+
+                when (val response = context.response.getOrNull()) {
+                    is DescribeEndpointsResponse -> discoveredHost = response.endpoints!!.first().address
+
+                    is ListScheduledQueriesResponse -> {
+                        // Make sure every request _except_ DescribeEndpoints uses the discovered endpoint
+                        assertNotNull(discoveredHost)
+                        assertEquals(discoveredHost, context.protocolRequest!!.url.host.toString())
+                    }
+
+                    else -> error("Unexpected response ${context.response}")
+                }
+            }
+        }
+
+        TimestreamQueryClient {
+            region = "us-west-2"
+            interceptors += interceptor
+        }.use { tsq ->
+            tsq.listScheduledQueries()
+
+            // Have to discover the endpoint the first time
+            assertEquals(listOf("DescribeEndpoints", "ListScheduledQueries"), operationLog)
+            operationLog.clear()
+
+            tsq.listScheduledQueries()
+
+            // Don't have to discover the endpoint again because it's cached
+            assertEquals(listOf("ListScheduledQueries"), operationLog)
+        }
+    }
+}