In general, a stakeholder is someone who has an interest or is concerned with the outcome of the project or activity or decision. This could be an individual, a group or an organization. Stakeholders can impact and / or be impacted by the outcome of the project. Test Managers must be able to identify software testing stakeholders and manage them effectively.
The primary responsibility of a Test Manager is to obtain resources like people, infrastructure, hardware, software, etc. and make maximum use of them to perform the testing processes.
These processes are usually part of an internal project led by Engineering or IT managers, which has to deliver the system or software or application to be used internally or externally.
Test Managers are concerned only with the testing processes. As these test processes enhance value of the product by supporting its overall success or averting severe failure, Test Manager needs to plan and control the test activities with this in mind.
The test processes, associated tasks and work products must be arrived at as per the stakeholders requirements, requirement specifications and software development life cycle.