About Software Testing

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Testing
Testing for an ATM simulator system involves various types of testing to ensure its
functionality, security, and user experience are up to standards. Here's a brief overview of the
types of testing typically performed:
Unit Testing
Unit Testing: This involves testing individual components or modules of the
ATM simulator system in isolation to ensure they work as intended. Unit tests
focus on small, specific functionalities such as user authentication, transaction
processing, and error handling.
Unit testing for an ATM simulator system involves testing individual
components or modules in isolation to ensure they function correctly. Here's a
brief overview of how unit testing is conducted:
Identification of Units: The first step in unit testing is to identify the smallest
testable parts of the ATM simulator system, such as functions, methods, or
classes.
Isolation of Units: Each unit is isolated from the rest of the system, along with
any dependencies it relies on. This can be achieved using techniques such as
mocking or stubbing to simulate the behaviour of external components.
Test Case Development: Test cases are developed to verify the behaviour and
functionality of each unit. These test cases typically cover different scenarios,
including normal operation, boundary cases, and error conditions.
Execution of Tests: The unit tests are executed using a testing framework or
tool. The tests validate the inputs, outputs, and internal state of each unit and
compare them against expected results.

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Assertion of Results: Assertions are used to verify that the actual results
produced by the unit match the expected results defined in the test cases. If
the actual results deviate from the expected results, the test fails, indicating a
potential issue in the unit.
Test Automation: Unit tests are often automated to facilitate frequent and
efficient testing during the development process. Automated unit tests can be
run automatically as part of a continuous integration (CI) pipeline or
development workflow.
Feedback and Debugging: When a unit test fails, developers receive immediate
feedback, allowing them to identify and debug the underlying issue. This
iterative process helps improve the quality and reliability of the ATM simulator
system.
By performing thorough unit testing, developers can identify and fix defects
early in the development cycle, ensuring that individual components of the
ATM simulator system work as intended and contribute to the overall
functionality and performance of the system.
Integration Testing
Integration testing for an ATM simulator system involves testing the
interactions between different modules or components to ensure they work
together seamlessly. Here's a brief overview of how integration testing is
conducted:
Identifying Integration Points: Integration testing begins by identifying the
integration points between various modules or components of the ATM
simulator system. These integration points are where data or control flow
between different parts of the system.

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Developing Integration Test Cases: Test cases are developed to verify the
interactions and data exchanges between integrated components. These test
cases are designed to cover different integration scenarios, including normal
operation, error conditions, and boundary cases.
Setting Up Test Environment: A test environment is set up to simulate the
runtime environment of the ATM simulator system. This environment may
include simulated hardware components, databases, external interfaces (such
as banking servers), and any other dependencies required for integration
testing.
Executing Integration Tests: Integration tests are executed to validate the
interactions between integrated components. The tests verify that data is
exchanged correctly, messages are passed between modules as expected, and
interfaces behave as intended.
Mocking or Stubs: In some cases, real components may be replaced with mock
objects or stubs to simulate the behaviour of external dependencies. This
allows integration testing to proceed even if certain components are not fully
implemented or available.
Validation of Outputs: The outputs produced by integrated components are
validated against expected results defined in the integration test cases. Any
discrepancies between actual and expected results are identified as potential
integration issues.
Error Handling and Recovery: Integration tests also evaluate the system's error
handling and recovery mechanisms. This involves testing how the system
responds to unexpected errors, faults, or exceptions during integration,
ensuring that it can recover gracefully and maintain data integrity.

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Regression Testing: After making changes or updates to the ATM simulator
system, regression tests are performed to ensure that existing integrations
have not been adversely affected. This helps detect and address any
regressions introduced by modifications to the system.
By conducting thorough integration testing, developers can ensure that
different components of the ATM simulator system integrate effectively,
communicate correctly, and function as a cohesive unit. Integration testing
helps identify and resolve integration issues early in the development process,
reducing the risk of defects and ensuring the reliability and stability of the
system.
Regression testing
Regression testing for an ATM simulator system involves retesting the
system after making changes or updates to ensure that existing
functionalities have not been adversely affected. Here's a brief overview
of how regression testing is conducted:
Test Case Selection: Test cases that cover critical functionalities of the
ATM simulator system are selected for regression testing. These test
cases typically include a combination of unit tests, integration tests, and
functional tests.
Baseline Establishment: A baseline is established by running the
selected test cases on the current version of the ATM simulator system,
also known as the baseline version. The results of these tests serve as a
reference point for comparison during regression testing.
Modification Implementation: Changes or updates are made to the ATM
simulator system, such as bug fixes, feature enhancements, or code
optimizations. These modifications may include changes to code,
configurations, or dependencies.

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Re-execution of Test Cases: The selected test cases are re-executed on
the modified version of the ATM simulator system to assess the impact
of the changes. The tests verify that existing functionalities still work as
expected and that the modifications have not introduced any unintended
side effects or regressions.
Comparison of Results: The results of the regression tests are compared
against the baseline results obtained from the initial test execution. Any
discrepancies or deviations between the current results and the baseline
results are identified as potential regression issues.
Investigation and Debugging: If regression issues are detected,
developers investigate the root causes of the problems and debug the
code to address them. This may involve analysing code changes,
reviewing logs, and performing additional testing to isolate and fix the
issues.
Iterative Process: Regression testing is an iterative process that may be
repeated multiple times as changes are made to the ATM simulator
system. Each iteration of regression testing helps ensure that the system
remains stable and functional throughout the development lifecycle.
Automation: To facilitate efficient regression testing, automated testing
frameworks or tools may be used to automate the execution of
regression test cases. Automated regression testing helps speed up the
testing process and enables frequent regression testing as part of a
continuous integration (CI) or continuous delivery (CD) pipeline.
By performing regression testing, developers can maintain the quality
and reliability of the ATM simulator system, ensuring that existing
functionalities continue to work correctly even after making changes or
updates to the software. Regression testing helps prevent the
introduction of regressions and ensures a smooth and stable user
experience for ATM users.

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Functional testing
Functional testing for an ATM simulator system involves evaluating the
system's functionalities to ensure they meet the specified requirements.
Here's a brief overview of how functional testing is conducted:
Requirement Analysis: The first step in functional testing is to understand
the functional requirements of the ATM simulator system. This involves
reviewing the system's specifications, user stories, and other relevant
documentation to identify the expected behaviours’ and functionalities.
Test Case Development: Test cases are developed to validate each
functional requirement of the ATM simulator system. These test cases
are designed to cover various scenarios, including typical usage
patterns, boundary conditions, and error handling.
Test Environment Setup: A test environment is set up to simulate the
runtime environment of the ATM simulator system. This environment
may include simulated hardware components, databases, network
connections, and any other dependencies required for functional testing.
Test Execution: The developed test cases are executed on the ATM
simulator system to verify its functionalities. The tests may include
actions such as logging in, checking account balances, making
withdrawals, depositing funds, transferring money between accounts,
and printing transaction receipts.
Input Validation: Functional tests verify that the ATM simulator system
correctly validates user inputs, such as PINs, account numbers, and
transaction amounts. Invalid inputs should result in appropriate error
messages and prevent unauthorized actions.
Output Verification: The outputs produced by the ATM simulator system,
such as transaction receipts, account balances, and error messages, are

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compared against expected results defined in the test cases. Any
discrepancies between actual and expected outputs are flagged as
potential issues.
Boundary Testing: Boundary testing is performed to validate the
behaviour of the ATM simulator system at the boundaries of input
ranges. This ensures that the system handles maximum and minimum
values, edge cases, and special conditions correctly.
Error Handling Testing: Functional tests also evaluate the system's error
handling capabilities. This involves deliberately triggering errors, faults,
or exceptions to assess how the ATM simulator system responds and
whether it provides appropriate error messages and recovery
mechanisms.
Regression Testing: After making changes or updates to the ATM
simulator system, regression tests are conducted to ensure that existing
functionalities have not been adversely affected. Regression testing
helps detect and address any regressions introduced by modifications to
the system.
By performing functional testing, developers can verify that the ATM
simulator system behaves as expected, meets user requirements, and
delivers a reliable and consistent user experience. Functional testing
helps identify and address issues early in the development process,
ensuring the quality and correctness of the software.