Testing Interview Questions

1. What is load testing?
Load testing is to test that the application works with the loads that results from large number of simultaneous users , transactions and to determine whether it can handle peak usage periods.

2. What is performance testing?
Timing for both read and update transaction should be gathered to determine whether system functions or being performed in an acceptable time frame. This should be done standalone and then in a multi user environment to determine the effect of multiple transactions on the timing of a single transaction.

3. Explain the load testing process?
Step1: Planning the test: Here, we develop a clearly defined test plan to ensure the test scenarios we develop will accomplish load testing objectives.
Step2: Creating Vusers: Here, we create Vuser scripts that contain tasks performed by each Vusers, tasks performed by Vusers as whole, and tasks measured as transactions.
step3: Creating the scenario: A scenario describes the events that occurred during the testing session.It includes a list of machines scripts and Vusers that run during the scenario. We create scenarios using load runner controller. We can create manual scenarios as well as goal oriented scenarios. In manual scenarios, we defined the number of Vusers, the load generated machines, and percentage of Vusers to be assigned to each script. For web tests we may create a goal oriented scenario where we define the goal that our test has to achieve. Load runner automatically builds a scenarios for us.
step4: Running the Scenario: We emulate load on the server by instructing multiple Vusers to perform tasks simultaneously. Before the testing, we set the scenario configuration and scheduling. We can run the entire scenario, Vuser groups, or individual Vusers.
Step5: Monitoring the scenario: We monitor scenario execution using the load runner online run time transaction system resource, web resource, web server resource, web application server resource, database server resource, network delay, streaming media resource, firewall server resource, ERP server resource and Java performance monitors
Step6: Analyzing the Test results: During the scenario execution LR records the performance of the application under different loads. We use load runner’s graphs and reports to analyze the application performance.

4. When do you do load and performance testing?
We perform load testing once we are done with interface (GUI) testing. Modern system architectures are large and complex. Where as single user testing primarily on functionality and user interface of a system component, application testing focuses on performance and reliability of an entire system. For Ex: A typical application testing scenario might depict 1000 users login in simultaneously to a system. This gives rise to issues such as what is the response time of the system, does it crash, will it go with different software application and platform, can it hold so many 100’s and 1000’s of users etc.. This is when we set to do load and performance testing.

5. What are the components of load runner?
The components of load runner are the virtual user generator, controller, the agent process, load runner analysis and monitoring, load runner books online.

6. What component of load runner would you use to record a script?
The Virtual user generator (VuGen) component is used to record a script. It enable you to develop Vuser scripts for a variety of application types and communication protocols.

7. What component of Load runner would you use to playback the script in multi user mode?
The controller component is used to playback the script in multiuser mode. This is done during the scenario run where a Vuser script is executed by number of Vusers in a group.

8. What is a rendezvous point?
You insert rendezvous point into Vuser scripts to emulate heavy user load on the server. Rendezvous point instructs Vusers to wait during the test execution for multiple Vusers to arrive at certain point, in order that they may simultaneously perform a task. for Ex. To emulate peak load on the bank server, you can insert a rendezvous point instructing 100 Vusers to deposit cash into their accounts at the same time.

9. What is a Scenario?
A Scenario defines the events that occur during each testing sessions. For example a scenario defines and controls the number of user to emulate, the actions to be performed, and the machines on which the virtual users run their emulations.

10. Explain the recording mode for Web Vuser Script?
We use VuGen to develop a Vuser script by recording a user performing typical business process on a client application. VuGen creates a script by recording the activity between the client and server. For example, in web based application, VuGen monitors the client end of database and traces all the request sent to, and receive the database server. We use VuGen to monitor the communication between the application and server, Generates the required function calls and insert the generated function calls into a Vuser script.

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