Test Plan vs Test Strategy vs Test Approach

                Test Plan vs Test Strategy vs Test Approach 

                                                                Test Plan

                                                                       |

                                                              Test Strategy

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                                                             Test Approach

    The above flow diagram illustrates that First Test Plan is created which includes test strategy &

test Strategy includes the test Approach

Theory Says – 

Test Plan - “A software project test plan is a document that describes the objectives, scope, approach, and focus of a software testing effort” 
The purpose of the Master Test Plan, as stated by the IEEE Std 829 is to provide an overall test planning and test management document for multiple levels of test (either within one project or across multiple projects). 
You can see the IEEE standard test plan is here. 

Test Strategy – Test Strategy or Test Approach is a set of guide lines that describes test design. Test strategy says - How testing is going to be performed? What will be the test architecture? 
Test Strategy can be at two levels – Company/Organization Level and Project Level. For e,g, If company is product based, then there can be a general test strategy for testing their software products. Same strategy can be implemented (with/without  some modifications) at project level whenever a new project comes. 
Might be these are OK for beginners, but actually this is not enough. 

Test approach -- "It's the way how do you do your testing." Test Approach is created by the individual tester/TestLead according to the module or application means his own views or approaches for that Module.

Example: Test plan gives the information of who is going to test at what time. For example: Module 1 is going to be tested by “X tester”. If tester Y replaces X for some reason, the test plan has to be updated.

On the contrary, test strategy is going to have details like – “Individual modules are to be tested by test team members & there should be more than 85% automation for each module“ In this case, it does not matter who is testing it- so it’s generic and the change in the team member does not have to be updated, keeping it static.

& test approach will be decided the by the test Lead/tester that which tool will be used for automation . Ex. for UI whether to use selenium or QTP... for API whether to use the restAssuerd or SOAPUI