TL;DR

This post answers the questions what is software tester mission and why is important that software tester has a mission. This answer is aligned with Black Box Software Testing Foundations course (BBST) created by Rebecca Fiedler, Cem Kaner and James Bach.

Definition

How do you explain, or better put, how do you tell a story about your software testing? Why you are testing product using specific test technique?

Software testing mission is answer to the question, Why are you testing?

Explanation

You are testing to achieve your PRIMARY INFORMATION objectives.

That means that information objectives are directing your testing. Knowing that, you are on good path to become excellent tester.

Here are dictionary definitions for main ingredients of software testing mission.

[Objective], noun, a thing aimed at or sought; a goal: the system has achieved its objective.

[Primary], adjective, of chief importance; principal: the government's primary aim is to see significant reductions in unemployment.

[Information], noun, facts provided or learned about something or someone: a vital piece of information.

So we have two nouns and adjective, not a word about software programming (although, it could help in testing activities).

It is ok to have several information objectives, but one mission should cover one or two objectives, otherwise your testing will lose focus and would become fragmented. Your mission would not be achievable.

Example

In previous post, we explained software testing context. Context defines your mission. For example, in project with 24 2 week sprints, in first three sprints you would learn the product, with zero bug reporting.  In the middle of the project, you would hunt for bugs, because you learned how product should work (you have your oracles). To the end, you will do regression tests and tests for fixed bugs.

Time is important testing variable. Remember, do not try to achieve several mission at the SAME time.