Writing test scenarios with Gatlings simulation and scenario builders
Gatling provides two main components for writing test scenarios: the simulation and the scenario builder. The simulation is a high-level description of a test scenario that specifies the actions that users will perform, the number of users to simulate, and the duration of the test. The scenario builder is a lower-level component that is used to specify the individual steps or requests that make up a user's actions.
With Gatling's simulation and scenario builder, it's possible to write complex test scenarios that closely reflect real-world usage patterns. For example, you can simulate a scenario where a large number of users log into a web application, perform various actions, and then log out. This can involve multiple steps or requests, such as sending a login request, accessing different pages, submitting forms, and more.
To write a complex test scenario in Gatling, you typically start by defining the simulation, which includes the following elements:
- The number of users to simulate
- The ramp-up period, which specifies the time it takes to ramp up to the full number of users
- The duration of the test
Next, you use the scenario builder to define the individual steps or requests that make up the user's actions. The scenario builder provides a number of methods for sending requests, handling responses, and defining conditions for branching or looping.
Gatling also provides a number of convenient methods for simulating common use cases, such as sending requests at a constant rate, using random data for form submissions, and more. Additionally, Gatling provides a rich set of assertions for validating responses and verifying that the application behaves as expected.
With Gatling's simulation and scenario builder, you have a lot of flexibility and control over how you define and run your tests. You can write simple or complex test scenarios, and you can use Gatling's rich set of features to get a detailed understanding of your application's performance under heavy loads.
Here's a simple example of how you might write a complex test scenario using Gatling's simulation and scenario builder:
import io.gatling.core.Predef._
import io.gatling.http.Predef._
import scala.concurrent.duration._
class BasicSimulation extends Simulation {
val httpProtocol = http
.baseUrl("http://localhost:8080")
.acceptHeader("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
.doNotTrackHeader("1")
.acceptLanguageHeader("en-US,en;q=0.5")
.acceptEncodingHeader("gzip, deflate")
.userAgentHeader("Mozilla/5.0 (Windows NT 5.1; rv:40.0) Gecko/20100101 Firefox/40.0")
val scn = scenario("BasicSimulation")
.exec(http("request_1")
.get("/"))
.pause(5)
.exec(http("request_2")
.get("/search?q=gatling"))
.pause(1)
.exec(http("request_3")
.get("/cart"))
.pause(2)
.exec(http("request_4")
.post("/purchase")
.formParam("itemId", "12345"))
.pause(3)
.exec(http("request_5")
.get("/confirmation"))
setUp(
scn.inject(rampUsers(100) during (10 seconds))
).protocols(httpProtocol)
}
In this example, we define a simulation called BasicSimulation that extends the Simulation class provided by Gatling. The simulation is defined with a number of exec methods that specify the individual requests that make up the scenario. In between each request, we use the pause method to specify a pause time in seconds.
We also define an HTTP protocol that specifies the default headers that should be included in each request. This protocol is later passed to the protocols method to set it as the default for the simulation.
Finally, we use the setUp method to specify how many users to simulate and for how long. In this case, we're ramping up to 100 users over a 10-second period.
With this simulation defined, we can run Gatling and see how our web application performs under heavy loads. Gatling will generate a detailed report that provides information about the performance of each request, including response times, error rates, and more.
Leave a Comment