Mainframe Testing – Complete Tutorial

A mainframe is a powerful and high-speed computer system designed for handling large-scale computing tasks that demand high availability and robust security. It finds extensive application in critical sectors such as finance, insurance, retail, and other industries that necessitate the processing of vast volumes of data repeatedly.

Mainframe Testing

Mainframe Testing involves the verification and validation of software applications and services that rely on Mainframe Systems. This testing aims to ensure the readiness, performance, reliability, and overall quality of the software before deployment.

In Mainframe Testing, testers primarily focus on navigating through CICS screens, which are tailored to specific applications. They do not need to be concerned about setting up emulators on their machines or worry about compatibility, as changes made to the code in languages like COBOL or JCL will work across various terminal emulators.

The testing process typically involves assessing the deployed code against predefined test cases based on requirements. Different combinations of data are fed into the input file to evaluate the application’s behavior. To access applications on the mainframe, users employ a terminal emulator, which is the only required software to be installed on the client’s machine.

Mainframe Attributes:

Virtual Storage:

• This technique allows a processor to emulate a main storage that is larger than the actual amount of real storage.
• It enables effective memory utilization for storing and executing tasks of various sizes.
• Disk storage is utilized as an extension of real storage.

Multiprogramming:

• In a multiprogramming environment, the computer executes more than one program simultaneously. However, at any given moment, only one program can have control of the CPU.
• It is a facility provided to optimize CPU utilization.

Batch Processing:

• Batch processing involves accomplishing tasks in units known as jobs.
• A job may trigger the execution of one or more programs in a specific sequence.
• The job scheduler determines the order in which jobs should be executed to maximize average throughput. Priority and class are considered in job scheduling.
• Batch processing is described using JCL (Job Control Language), which outlines the batch job, including programs, data, and required resources.

Time Sharing:

• Time-sharing systems allow each user to access the system through a terminal device. Instead of submitting jobs scheduled for later execution, users input commands that are processed immediately.
• This enables interactive processing, allowing users to directly interact with the computer.
• Time-share processing is referred to as “Foreground Processing,” while batch job processing is known as “Background Processing.”

Spooling (Simultaneous Peripheral Operations Online):

• Spooling involves using a SPOOL device to store the output of programs or applications. The spooled output can be directed to output devices like printers if necessary.
• It leverages buffering to efficiently utilize output devices.

Classification of Manual Testing in Mainframe

• Unit Testing:

This involves testing individual components or units of code to ensure they work as intended. It focuses on verifying the correctness of specific functions, subroutines, or modules.

• Integration Testing:

Integration testing in Mainframe verifies the interactions and interfaces between different components or modules. It ensures that data flows correctly between integrated units.

• System Testing:

System testing evaluates the entire mainframe application to confirm that it meets the specified requirements. It covers end-to-end testing and checks the overall functionality of the system.

• Acceptance Testing:

Acceptance testing involves validating the system against business requirements and user expectations. It ensures that the mainframe application meets the criteria set by the stakeholders.

• Regression Testing:

Regression testing verifies that recent changes or enhancements to the mainframe application do not introduce new defects or negatively impact existing functionalities.

• User Acceptance Testing (UAT):

UAT is conducted by end-users or business stakeholders to validate that the mainframe application meets their specific business needs. It provides confidence that the system is ready for production deployment.

• Compatibility Testing:

Compatibility testing ensures that the mainframe application functions correctly across different environments, such as various operating systems, browsers, or hardware configurations.

• Security Testing:

Security testing focuses on identifying vulnerabilities, threats, and risks related to data security and access controls within the mainframe application.

• Performance Testing:

Performance testing assesses the responsiveness, scalability, and stability of the mainframe application under different load conditions. It ensures that the system can handle expected levels of user activity.

• Usability Testing:

Usability testing evaluates the user-friendliness and user interface of the mainframe application. It assesses how easily users can navigate and perform tasks within the system.

• Documentation Testing:

Documentation testing involves reviewing and validating all the documentation related to the mainframe application, including user manuals, technical guides, and system documentation.

• Recovery Testing:

Recovery testing assesses the ability of the mainframe application to recover from failures or system crashes. It ensures that data integrity is maintained and operations can resume after a disruption.

How to do Mainframe Testing?

Performing Mainframe Testing involves several steps to ensure the functionality, reliability, and performance of mainframe applications. Here’s a step-by-step guide on how to conduct Mainframe Testing:

• Understanding Requirements:

Start by thoroughly understanding the requirements and specifications of the mainframe application. This includes reviewing the business rules, data formats, input/output specifications, and any other relevant documentation.

• Environment Setup:

Set up the testing environment, which includes configuring the mainframe system, emulator software, and any additional tools or resources needed for testing.

• Test Planning:

Create a detailed test plan that outlines the scope, objectives, resources, schedule, and deliverables of the testing process. Define the types of tests to be conducted, such as unit testing, integration testing, system testing, etc.

• Test Data Preparation:

Generate or gather the test data required for different test scenarios. This data should cover various scenarios, including boundary cases, valid inputs, and invalid inputs.

• Test Case Design:

Develop test cases based on the requirements and specifications. Test cases should include input data, expected results, and steps to execute the test. Create both positive and negative test cases to ensure comprehensive coverage.

• Unit Testing:

Start with unit testing, where individual components or modules of the mainframe application are tested in isolation. Verify that each unit functions correctly according to its specifications.

• Integration Testing:

Conduct integration testing to verify the interactions between different modules or components. Ensure that data flows correctly and that integrated units work together as expected.

• System Testing:

Perform end-to-end testing of the entire mainframe application. Validate that the system meets the specified requirements and functions as a cohesive whole.

• Regression Testing:

After any code changes or enhancements, execute regression tests to ensure that existing functionalities are not negatively affected. Verify that new changes do not introduce new defects.

• User Acceptance Testing (UAT):

Collaborate with end-users or business stakeholders to conduct UAT. They should validate that the mainframe application meets their business needs and requirements.

• Performance Testing:

Evaluate the performance of the mainframe application under different load conditions. This includes tests for responsiveness, scalability, and stability.

• Security Testing:

Assess the security measures of the mainframe application. Identify vulnerabilities, risks, and potential security breaches. Ensure that data is protected and access controls are enforced.

• Documentation Review:

Review and validate all documentation related to the mainframe application, including user manuals, technical guides, and system documentation.

• Defect Logging and Management:

Document any defects or issues encountered during testing. Clearly describe the problem, steps to reproduce, and expected vs. actual results. Track the status of each defect until resolution.

• Reporting and Documentation:

Prepare test reports summarizing the testing activities, results, and any identified issues. Include details on test coverage, pass/fail status, and recommendations for further action.

• Closure and Sign-off:

Obtain sign-off from stakeholders indicating their acceptance of the testing results. Ensure that all identified defects have been addressed and resolved.

Methodology in Mainframe Testing

Mainframe Testing Methodology involves a structured approach to testing applications that run on mainframe systems. It aims to ensure the functionality, reliability, and performance of mainframe applications.

• Requirement Analysis:

Understand the business requirements and gather detailed specifications for the mainframe application. This includes studying functional requirements, data formats, and system behavior.

• Environment Setup:

Configure the testing environment, including the mainframe system, emulator software, databases, and any other necessary tools or resources.

• Test Planning:

Create a comprehensive test plan that outlines the scope, objectives, resources, schedule, and deliverables of the testing process. Define the types of tests to be conducted (unit, integration, system, etc.).

• Test Data Preparation:

Generate or collect the test data needed to execute different test scenarios. Ensure that the data covers a wide range of scenarios, including boundary cases and error conditions.

• Test Case Design:

Develop test cases based on the requirements and specifications. Each test case should include input data, expected results, and step-by-step instructions for executing the test.

• Unit Testing:

Begin with unit testing, where individual modules or components of the mainframe application are tested in isolation. Verify that each unit functions correctly according to its specifications.

• Integration Testing:

Test the interactions between different modules or components. Ensure that data flows correctly and that integrated units work together as expected.

• System Testing:

Perform end-to-end testing of the entire mainframe application. Validate that the system meets the specified requirements and functions as a cohesive whole.

• Regression Testing:

After any code changes or enhancements, execute regression tests to ensure that existing functionalities are not negatively affected. Verify that new changes do not introduce new defects.

• User Acceptance Testing (UAT):

Collaborate with end-users or business stakeholders to conduct UAT. They should validate that the mainframe application meets their business needs and requirements.

• Performance Testing:

Evaluate the performance of the mainframe application under different load conditions. This includes tests for responsiveness, scalability, and stability.

• Security Testing:

Assess the security measures of the mainframe application. Identify vulnerabilities, risks, and potential security breaches. Ensure that data is protected and access controls are enforced.

• Documentation Review:

Review and validate all documentation related to the mainframe application, including user manuals, technical guides, and system documentation.

• Defect Logging and Management:

Document any defects or issues encountered during testing. Clearly describe the problem, steps to reproduce, and expected vs. actual results. Track the status of each defect until resolution.

• Reporting and Documentation:

Prepare test reports summarizing the testing activities, results, and any identified issues. Include details on test coverage, pass/fail status, and recommendations for further action.

• Closure and Sign-off:

Obtain sign-off from stakeholders indicating their acceptance of the testing results. Ensure that all identified defects have been addressed and resolved.

Commands used in Mainframe Testing

1. TSO (Time Sharing Option):

   • TSO is the primary command interface for interacting with a mainframe system. It provides a command-line environment for performing various tasks.

Example Commands:

• TSO LOGON userid – Log in to the mainframe system.
• TSO LOGOFF – Log out of the mainframe system.
• TSO SUBMIT – Submit a batch job for execution.

2. ISPF (Interactive System Productivity Facility):

   • ISPF is a menu-driven interface that provides a more user-friendly environment for interacting with the mainframe.

Example Commands:

• ISPF – Launch the ISPF environment.
• ISPF 3.4 – Access the Data Set List Utility to view and manage datasets.

3. JCL (Job Control Language):

   • JCL is used to define and submit batch jobs for execution on the mainframe.

Example Commands:

• //JOBNAME JOB … – Define a job and specify its parameters.
• //STEP EXEC PGM=program – Define a step in a batch job.

4. IDCAMS (Access Method Services):

   • IDCAMS is a utility for managing datasets and their attributes.

Example Commands:

• DELETE dataset – Delete a dataset.
• PRINT dataset – Print the contents of a dataset.

5. FTP (File Transfer Protocol):

   • FTP is used to transfer files between the mainframe and other systems.

Example Commands:

• FTP hostname – Connect to an FTP server.
• GET filename – Download a file from the server.

6. IEFBR14:

   • IEFBR14 is a dummy utility program that does nothing but return a completion code.

Example Command:

• IEFBR14 – Submit a job that uses the IEFBR14 program.

7. SORT (Sort/Merge Utility):

   • SORT is used for sorting and merging datasets.

Example Commands:

• SORT FIELDS=(start,length,format,A/D) – Define sorting criteria.
• OUTFIL … – Define output specifications.

8. SED (Screen Editor):

   • SED is used for editing datasets interactively.

Example Commands:

• SED dataset – Start the screen editor for a dataset.
• CHANGE ‘old’ ‘new’ – Search and replace text in the dataset.

9. REPRO (Copy Utility):

   • REPRO is used for copying datasets.

Example Commands:

• REPRO INFILE(dataset1) OUTFILE(dataset2) – Copy data from one dataset to another.

10. SUBMIT (Batch Job Submission):

    • SUBMIT is used to submit a batch job for execution.

Example Command:

• SUBMIT jobname – Submit a batch job.

Pre-requisites to start mainframe testing

• Basic Mainframe Knowledge:

Testers should have a fundamental understanding of mainframe architecture, components, and terminology. This includes knowledge of terms like TSO, JCL, CICS, VSAM, etc.

• Access to Mainframe Environment:

Testers need access to a mainframe environment for testing purposes. This may involve obtaining login credentials and permissions from the system administrators.

• Understanding of JCL (Job Control Language):

Testers should be familiar with JCL, as it is used for creating and submitting batch jobs. Knowledge of basic JCL syntax and statements is essential.

• Knowledge of Data Formats:

Mainframe systems often handle data in specific formats like EBCDIC. Testers should understand these formats and how to work with them.

• Familiarity with Test Data Generation:

Testers should be skilled in generating relevant test data for different scenarios. This includes understanding data requirements and how to manipulate it.

• Knowledge of Test Case Design:

Testers should be able to design test cases that cover various scenarios, including positive, negative, and boundary cases.

• Understanding of Batch and Online Testing:

Testers should know the difference between batch and online processing on the mainframe and be prepared to test both types of applications.

• Use of Test Tools:

Familiarity with any testing tools specific to the mainframe environment (if applicable) is beneficial.

• Knowledge of Mainframe Testing Tools:

Knowledge of tools like File-AID, QMF, Expeditor, etc., that are commonly used in mainframe testing can be an advantage.

• Communication Skills:

Effective communication is crucial, as testers may need to collaborate with mainframe developers, system administrators, and other stakeholders.

• Documentation Skills:

Testers should be proficient in documenting test cases, test results, and any defects found during testing.

• Problem-Solving Skills:

Testers should have good analytical and problem-solving abilities to identify, isolate, and report defects accurately.

• Attention to Detail:

Mainframe applications often process large volumes of data. Testers need to pay close attention to detail to ensure accurate results.

• Security Awareness:

Testers should be aware of the security protocols and best practices specific to mainframe environments.

• Regression Testing Skills:

Understanding of regression testing concepts and techniques is important for validating that changes do not introduce new defects.

Mainframe testing Challenges and Troubleshooting

Challenges:

• Limited Access to Mainframe Environment:

Troubleshooting: Work closely with system administrators to ensure testers have the necessary access rights. Provide adequate training on navigating the mainframe environment.

• Complexity of Mainframe Applications:

Troubleshooting: Break down testing tasks into manageable chunks. Prioritize critical functionalities and focus on thorough testing of high-impact areas.

• Diverse Technologies and Languages:

Troubleshooting: Provide training in relevant languages like COBOL, JCL, CICS, etc. Leverage automation tools to streamline testing processes.

• Data Manipulation and Validation:

Troubleshooting: Develop comprehensive data sets and validation procedures. Implement data generation tools for generating test data.

• Integration with Modern Technologies:

Troubleshooting: Use middleware and connectors for seamless integration between mainframe and modern systems. Implement effective data exchange protocols.

• Dependency on Legacy Systems:

Troubleshooting: Ensure thorough regression testing when changes are made to legacy systems. Implement strategies for minimizing impact on existing functionalities.

• Performance and Scalability Testing:

Troubleshooting: Conduct thorough performance testing to identify bottlenecks and optimize resource utilization. Scale testing environments to simulate real-world usage.

• Security Concerns:

Troubleshooting: Implement robust security protocols and encryption methods. Regularly conduct security audits and penetration testing.

• Testing Tools and Resources:

Troubleshooting: Provide access to specialized testing tools for Mainframe Testing. Ensure that testers are trained in using these tools effectively.

Troubleshooting Strategies:

• Collaborate with Mainframe Developers:

Engage in regular discussions with mainframe developers to understand the intricacies of the application and address any testing challenges.

• Detailed Documentation:

Maintain comprehensive documentation of test cases, test data, and results. This helps in identifying and reproducing issues efficiently.

• Use of Specialized Testing Tools:

Leverage specialized testing tools like Compuware, IBM Rational, etc., to streamline testing processes and address specific mainframe testing challenges.

• Root Cause Analysis:

When issues are identified, conduct thorough root cause analysis to understand the underlying problems and implement effective solutions.

• Continuous Learning and Training:

Provide ongoing training to testers on mainframe technologies, testing best practices, and troubleshooting techniques.

• Engage with Mainframe Experts:

Seek guidance and mentorship from experienced mainframe professionals who can provide valuable insights and solutions.

• Implement Automation:

Automate repetitive and time-consuming tasks to improve efficiency and accuracy in testing processes.

Common Abends encountered

In Mainframe Testing, an “abend” (short for abnormal end) refers to an unexpected termination or abnormal termination of a program. These abends can occur due to various reasons, such as programming errors, data inconsistencies, or system faults. Common abends encountered in Mainframe Testing:

• S0C1 – Operation Exception:

This abend occurs when a program attempts to perform an arithmetic operation on invalid data.

• S0C4 – Protection Exception:

This abend is caused by an attempt to access an area of storage that is not available to the program.

• S0C7 – Data Exception:

This abend occurs when there is an invalid data conversion or a violation of data definition.

• S0CB – Stack Overflow Exception:

This abend happens when a program exhausts its storage allocation.

• S0CC – Stack Underflow Exception:

This abend occurs when a program tries to pop data from an empty stack.

• S0CD – Divide Check Exception:

This abend occurs when a program attempts to divide a number by zero.

• S0CE – Multiply Check Exception:

This abend occurs when a program attempts to multiply two numbers, resulting in an overflow.

• S222 – Time-Out Abend:

This abend occurs when a program exceeds the maximum permitted CPU time.

• S806 – Program Load Error:

This abend happens when there is an issue with loading a program into memory.

• S822 – Data Exception Abend:

This abend is caused by an invalid or incorrect data format.

• S878 – Insufficient Virtual Storage:

This abend occurs when a program exhausts its allocated virtual storage.

• S806 – Abend in the Load Module:

This abend is caused by a load module error.

• S913 – Insufficient Space in DD Statement:

This abend occurs when there is insufficient space allocated for a DD statement.

• S0CB – Invalid Program Load:

This abend is caused by an attempt to load an invalid program.

• S013 – Insufficient Disk Space:

This abend occurs when there is insufficient space on a disk.

• S013 – File Not Found:

This abend happens when a required file cannot be found.

• S522 – JOB or TSO session terminated due to an error:

This abend is triggered by an error in the job or TSO session.

Common issue faced during mainframe testing

1. Data Inconsistencies:
   • Issue: Mismatched or incorrect data in files or databases.
   • Solution: Verify data sources, ensure data integrity, and perform thorough data validation.

2. JCL Errors:

   • Issue: Job Control Language (JCL) errors in job execution.
   • Solution: Review and debug JCL statements for syntax errors, missing parameters, or incorrect dataset references.

3. Abnormal Ends (Abends):

   • Issue: Unexpected terminations of programs due to errors or exceptions.
   • Solution: Analyze abend codes, review program logic, and perform debugging to identify and fix the root cause.

4. Integration Issues:

   • Issue: Incompatibility or miscommunication between different components or systems.
   • Solution: Conduct thorough integration testing, verify data flows, and ensure seamless interaction between modules.

5. Performance Bottlenecks:

   • Issue: Slow response times or system crashes under load.
   • Solution: Conduct performance testing to identify bottlenecks, optimize code, and enhance system resource allocation.

6. Security Vulnerabilities:

   • Issue: Potential security risks or vulnerabilities in the mainframe application.
   • Solution: Perform security testing, address authentication and authorization mechanisms, and implement encryption protocols.

7. File Handling Errors:

   • Issue: Incorrect file operations, such as reading from or writing to the wrong datasets.
   • Solution: Validate file references, ensure proper file allocation, and verify file attributes.

8. Resource Constraints:

   • Issue: Insufficient memory, CPU capacity, or other system resources.
   • Solution: Optimize resource allocation, review system configurations, and adjust job priorities.

9. Batch Processing Issues:

   • Issue: Failures in batch jobs or incorrect sequencing of tasks.
   • Solution: Review batch job dependencies, validate job schedules, and ensure proper job sequencing.

10. Data Privacy Compliance:

    • Issue: Non-compliance with data privacy regulations (e.g., GDPR).
    • Solution: Implement data masking or anonymization techniques, and ensure compliance with relevant regulations.

11. Documentation Gaps:

    • Issue: Insufficient or outdated documentation for mainframe components.
    • Solution: Keep documentation up-to-date, maintain comprehensive test cases, and provide training for testers.

12. Tooling and Environment Setup:

    • Issue: Challenges in configuring and setting up mainframe testing tools and environments.
    • Solution: Leverage specialized tools, seek assistance from experienced mainframe teams, and ensure proper environment configurations.

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