test: add load test for session creation (#8088)

# Which Problems Are Solved

Extends load tests by testing session creation.

# How the Problems Are Solved

The test creates a session including a check for user id.

# Additional Context

- part of https://github.com/zitadel/zitadel/issues/7639

load-test/src/use_cases/machine_client_credentials_login.ts

@@ -0,0 +1,49 @@
+import { loginByUsernamePassword } from '../login_ui';
+import { createOrg, removeOrg } from '../org';
+import {createMachine, User, addMachineSecret} from '../user';
+import {clientCredentials, userinfo} from '../oidc';
+import { Config, MaxVUs } from '../config';
+
+export async function setup() {
+  const tokens = loginByUsernamePassword(Config.admin as User);
+  console.info('setup: admin signed in');
+
+  const org = await createOrg(tokens.accessToken!);
+  console.info(`setup: org (${org.organizationId}) created`);
+
+  let machines = (
+    await Promise.all(
+      Array.from({ length: MaxVUs() }, (_, i) => {
+        return createMachine(`zitachine-${i}`, org, tokens.accessToken!);
+      }),
+    )
+  ).map((machine) => {
+    return { userId: machine.userId, loginName: machine.loginNames[0] };
+  });
+  console.info(`setup: ${machines.length} machines created`);
+
+  let credentials = (
+    await Promise.all(
+      machines.map((machine) => {
+        return addMachineSecret(machine.userId, org, tokens.accessToken!);
+      }),
+    )
+  ).map((credentials, i) => {
+    return { userId: machines[i].userId, loginName: machines[i].loginName, password: credentials.clientSecret };
+  });
+  console.info(`setup: secrets added`);
+
+  return { tokens, machines: credentials, org };
+}
+
+export default function (data: any) {
+  clientCredentials(data.machines[__VU - 1].loginName, data.machines[__VU - 1].password)
+    .then((token) => {
+      userinfo(token.accessToken!)
+    })
+}
+
+export function teardown(data: any) {
+  removeOrg(data.org, data.tokens.accessToken);
+  console.info('teardown: org removed');
+}

load-test/src/use_cases/session.ts

@@ -0,0 +1,41 @@
+import { loginByUsernamePassword } from '../login_ui';
+import { createOrg, removeOrg } from '../org';
+import { User, createHuman } from '../user';
+import { Trend } from 'k6/metrics';
+import { Config, MaxVUs } from '../config';
+import { createSession } from '../session';
+import { check } from 'k6';
+
+export async function setup() {
+  const tokens = loginByUsernamePassword(Config.admin as User);
+  console.log('setup: admin signed in');
+
+  const org = await createOrg(tokens.accessToken!);
+  console.log(`setup: org (${org.organizationId}) created`);
+
+  const humanPromises = Array.from({ length: MaxVUs() }, (_, i) => {
+    return createHuman(`zitizen-${i}`, org, tokens.accessToken!);
+  });
+
+  const humans = (await Promise.all(humanPromises)).map((user) => {
+    return { userId: user.userId, loginName: user.loginNames[0], password: 'Password1!' };
+  });
+  console.log(`setup: ${humans.length} users created`);
+  return { tokens, users: humans, org };
+}
+
+const addSessionTrend = new Trend('add_session_duration', true);
+export default async function (data: any) {
+  const start = new Date();
+  const session = await createSession(data.users[__VU - 1], data.org, data.tokens.accessToken);
+
+  check(session, {
+    'add session is status ok': (s) => s.id !== "",
+  });
+  
+  addSessionTrend.add(new Date().getTime() - start.getTime());
+}
+
+export function teardown(data: any) {
+  removeOrg(data.org, data.tokens.accessToken);
+}