What are the Software Testing Types ?

Unit testing – Testing of individual software components or modules. Typically done by the programmer and not by testers, as it requires detailed knowledge of the internal program design and code. may require developing test driver modules or test harnesses.

Integration testing – Testing of integrated modules to verify combined functionality after integration. Modules are typically code modules, individual applications, client and server applications on a network, etc. This type of testing is especially relevant to client/server and distributed systems.

Functional testing – This type of testing ignores the internal parts and focus on the output is as per requirement or not. Black-box type testing geared to functional requirements of an application.

System testing – Entire system is tested as per the requirements. Black-box type testing that is based on overall requirements specifications, covers all combined parts of a system.

Smoke testing -Smoke testing is the initial testing process exercised to check whether the software under test is ready/stable for further testing.

Sanity testing - Testing to determine if a new software version is performing well enough to accept it for a major testing effort. If application is crashing for initial use then system is not stable enough for further testing and build or application is assigned to fix.

Regression testing – Testing the application as a whole for the modification in any module or functionality. Difficult to cover all the system in regression testing so typically automation tools are used for these testing types.

User Acceptance testing -Normally this type of testing is done to verify if system meets the customer specified requirements. User or customer do this testing to determine whether to accept application.

Load testing – Its a performance testing to check system behavior under load. Testing an application under heavy loads, such as testing of a web site under a range of loads to determine at what point the system’s response time degrades or fails.

Stress testing – System is stressed beyond its specifications to check how and when it fails. Performed under heavy load like putting large number beyond storage capacity, complex database queries, continuous input to system or database load.

Performance testing – Term often used interchangeably with ‘stress’ and ‘load’ testing. To check whether system meets performance requirements. Used different performance and load tools to do this.

Usability testing – User-friendliness check. Application flow is tested, Can new user understand the application easily, Proper help documented whenever user stuck at any point. Basically system navigation is checked in this testing.

Recovery testing – Testing how well a system recovers from crashes, hardware failures, or other catastrophic problems.

Security testing – Can system be penetrated by any hacking way. Testing how well the system protects against unauthorized internal or external access. Checked if system, database is safe from external attacks.

Compatibility testing – Testing how well software performs in a particular hardware/software/operating system/network environment and different combination s of above.

Alpha testing – In house virtual user environment can be created for this type of testing. Testing is done at the end of development. Still minor design changes may be made as a result of such testing.

Beta testing – Testing typically done by end-users or others. Final testing before releasing application for commercial purpose.

Software Testing Levels

1.Unit Testing is a level of the software testing process where individual units/components of a software/system are tested. The purpose is to validate that each unit of the software performs as designed.


2.Integration Testing is a level of the software testing process where individual units are combined and tested as a group. The purpose of this level of testing is to expose faults in the interaction between integrated units.

3.System Testing is a level of the software testing process where a complete, integrated system/software is tested. The purpose of this test is to evaluate the system’s compliance with the specified requirements.

4.Acceptance Testing is a level of the software testing process where a system is tested for acceptability. The purpose of this test is to evaluate the system’s compliance with the business requirements and assess whether it is acceptable for delivery.

What is fundamental test process in software testing?

1)    Planning and Control
2)    Analysis and Design
3)    Implementation and Execution
4)    Evaluating exit criteria and Reporting
5)    Test Closure activities

1)Planning and Control:

Test planning has following major tasks:
i.  To determine the scope and risks and identify the objectives of testing.
ii. To determine the test approach.
iii. To implement the test policy and/or the test strategy. (Test strategy is an outline that describes the testing portion of the software development cycle. It is created to inform PM, testers and developers about some key issues of the testing process. This includes the testing objectives, method of testing, total time and resources required for the project and the testing environments.).
iv. To determine the required test resources like people, test environments, PCs, etc.
v. To schedule test analysis and design tasks, test implementation, execution and evaluation.
vi. To determine the Exit criteria we need to set criteria such as Coverage criteria.(Coverage criteria are the percentage of statements in the software that must be executed during testing. This will help us track whether we are completing test activities correctly. They will show us which tasks and checks we must complete for a particular   level of testing before we can say that testing is finished.)

 Test control has the following major tasks:
i.  To measure and analyze the results of reviews and testing.
ii.  To monitor and document progress, test coverage and exit criteria.
iii.  To provide information on testing.
iv.  To initiate corrective actions.
v.   To make decisions.

2)  Analysis and Design:

Test analysis and Test Design has the following major tasks:
i.   To review the test basis. (The test basis is the information we need in order to start the test analysis and   create our own test cases. Basically it’s a documentation on which test cases are based, such as requirements, design specifications, product risk analysis, architecture and interfaces. We can use the test basis documents to understand what the system should do once built.)
ii.   To identify test conditions.
iii.  To design the tests.
iv.  To evaluate testability of the requirements and system.
v.  To design the test environment set-up and identify and required infrastructure and tools.

3)  Implementation and Execution:
During test implementation and execution, we take the test conditions into test casesand procedures and other testware such as scripts for automation, the test environment and any other test infrastructure. (Test cases is a set of conditions under which a tester will determine whether an   application is working correctly or not.)
(Testware is a term for all utilities that serve in combination for testing a software like scripts, the test environment and any other test infrastructure for later reuse.)

Test implementation has the following major task:i.  To develop and prioritize our test cases by using techniques and create test data for those tests. (In order to test a software application you need to enter some data for testing most of the features. Any such specifically identified data which is used in tests is known as test data.)
We also write some instructions for carrying out the tests which is known as test procedures.
We may also need to automate some tests using test harness and automated tests scripts. (A test harness is a collection of software and test data for testing a program unit by running it under different conditions and monitoring its behavior and outputs.)ii. To create test suites from the test cases for efficient test execution.
(Test suite is a collection of test cases that are used to test a software program   to show that it has some specified set of behaviours. A test suite often contains detailed instructions and information for each collection of test cases on the system configuration to be used during testing. Test suites are used to group similar test cases together.)iii. To implement and verify the environment.

Test execution has the following major task:i.  To execute test suites and individual test cases following the test procedures.ii. To re-execute the tests that previously failed in order to confirm a fix. This is known as confirmation testing or re-testing.
iii. To log the outcome of the test execution and record the identities and versions of the software under tests. The test log is used for the audit trial. (A test log is nothing but, what are the test cases that we executed, in what order we executed, who executed that test cases and what is the status of the test case (pass/fail). These descriptions are documented and called as test log.).iv. To Compare actual results with expected results.v. Where there are differences between actual and expected results, it report discrepancies as Incidents.

4)  Evaluating Exit criteria and Reporting:
Based on the risk assessment of the project we will set the criteria for each test level against which we will measure the “enough testing”. These criteria vary from project to project and are known as exit criteria.
Exit criteria come into picture, when:
– Maximum test cases are executed with certain pass percentage.
– Bug rate falls below certain level.
– When achieved the deadlines.

Evaluating exit criteria has the following major tasks:
i.  To check the test logs against the exit criteria specified in test planning.
ii.  To assess if more test are needed or if the exit criteria specified should be changed.
iii.  To write a test summary report for stakeholders.

5)  Test Closure activities:
Test closure activities are done when software is delivered. The testing can be closed for the other reasons also like:

• When all the information has been gathered which are needed for the testing.
• When a project is cancelled.
• When some target is achieved.
• When a maintenance release or update is done.

Test closure activities have the following major tasks:
i.  To check which planned deliverables are actually delivered and to ensure that all incident reports have been resolved.
ii. To finalize and archive testware such as scripts, test environments, etc. for later reuse.
iii. To handover the testware to the maintenance organization. They will give support to the software.
iv To evaluate how the testing went and learn lessons for future releases and projects.

What are the Software Testing Methods ?

1. Black-Box Testing
2. White-Box Testing
3. Grey-Box Testing

Black-Box Testing	White-Box Testing	Grey-Box Testing
The internal workings of an application need not be known.	Tester has full knowledge of the internal workings of the application.	The tester has limited knowledge of the internal workings of the application.
Also known as closed-box testing, data-driven testing, or functional testing.	Also known as clear-box testing, structural testing, or code-based testing.	Also known as translucent testing, as the tester has limited knowledge of the insides of the application.
Performed by end-users and also by testers and developers.	Normally done by testers and developers.	Performed by end-users and also by testers and developers.
Testing is based on external expectations - Internal behavior of the application is unknown.	Internal workings are fully known and the tester can design test data accordingly.	Testing is done on the basis of high-level database diagrams and data flow diagrams.
It is exhaustive and the least time-consuming.	The most exhaustive and time-consuming type of testing.	Partly time-consuming and exhaustive.
Not suited for algorithm testing.	Suited for algorithm testing.	Not suited for algorithm testing.
This can only be done by trial-and-error method.	Data domains and internal boundaries can be better tested.	Data domains and internal boundaries can be tested, if known.

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Types of Testing - Software Testing ?

Manual Testing

Manual testing includes testing a software manually, i.e., without using any automated tool or any script. In this type, the tester takes over the role of an end-user and tests the software to identify any unexpected behavior or bug. There are different stages for manual testing such as unit testing, integration testing, system testing, and user acceptance testing.

Testers use test plans, test cases, or test scenarios to test a software to ensure the completeness of testing. Manual testing also includes exploratory testing, as testers explore the software to identify errors in it.

Automation Testing

Automation testing, which is also known as Test Automation, is when the tester writes scripts and uses another software to test the product. This process involves automation of a manual process. Automation Testing is used to re-run the test scenarios that were performed manually, quickly, and repeatedly.

Apart from regression testing, automation testing is also used to test the application from load, performance, and stress point of view. It increases the test coverage, improves accuracy, and saves time and money in comparison to manual testing.

What are the principles of testing ?

1) Testing shows presence of defects: 
Testing can show the defects are present, but cannot prove that there are no defects. Even after testing the application or product thoroughly we cannot say that the product is 100% defect free. Testing always reduces the number of undiscovered defects remaining in the software but even if no defects are found, it is not a proof of correctness.

2) Exhaustive testing is impossible:
Testing everything including all combinations of inputs and preconditions is not possible. So, instead of doing the exhaustive testing we can use risks and priorities to focus testing efforts. For example: In an application in one screen there are 15 input fields, each having 5 possible values, then to test all the valid combinations you would need 30  517  578  125  (515) tests. This is very unlikely that the project timescales would allow for this number of tests. So, accessing and managing risk is one of the most important activities and reason for testing in any project.

3) Early testing:
In the software development life cycle testing activities should start as early as possible and should be focused on defined objectives.

4) Defect clustering: 
A small number of modules contains most of the defects discovered during pre-release testing or shows the most operational failures.

5) Pesticide paradox:
If the same kinds of tests are repeated again and again, eventually the same set of test cases will no longer be able to find any new bugs. To overcome this “Pesticide Paradox”, it is really very important to review the test cases regularly and new and different tests need to be written to exercise different parts of the software or system to potentially find more defects.

6) Testing is context depending: 
Testing is basically context dependent. Different kinds of sites are tested differently. For example, safety – critical software is tested differently from an e-commerce site.

7) Absence – of – errors fallacy:
If the system built is unusable and does not fulfil the user’s needs and expectations then finding and fixing defects does not help.

What is Verification & Validation ?

Verification	Validation
Verification addresses the concern: "Are you building it right?"	Validation addresses the concern: "Are you building the right thing?"
Ensures that the software system meets all the functionality.	Ensures that the functionalities meet the intended behavior.
Verification takes place first and includes the checking for documentation, code, etc.	Validation occurs after verification and mainly involves the checking of the overall product.
Done by developers.	Done by testers.
It has static activities, as it includes collecting reviews, walkthroughs, and inspections to verify a software.	It has dynamic activities, as it includes executing the software against the requirements.
It is an objective process and no subjective decision should be needed to verify a software.	It is a subjective process and involves subjective decisions on how well a software works.

What is Errors, Defect and Failure ?

Errors: Any Incorrect human action that produces a problem in the system is called an error.

Defect: Deviation from the expected behavior to the actual behavior of the system is called the defect.

Failure: The deviation identified by end-user while using the system is called a failure.