Explain what is meant by the term 'collection runner' and how it is used in testing.

Collection runner is a tool or feature that allows running a set of tests or requests as a single unit.

In the context of API testing, for example in Postman, the collection runner allows executing a series of requests from a collection automatically, which is convenient for regression testing or scenario verification.

In test automation, the collection runner helps to run groups of tests, manage their execution order, parameterize data, and collect reports.

Example of usage:

• Select a request collection in Postman
• Launch the collection runner
• Set the number of iterations, data for parameters
• Analyze the results after execution

Thus, the collection runner simplifies mass and sequential test execution.