Following are some of the key challenges of software testing:
The lack of availability of standard documents to understand the application
Lack of skilled testers
Understanding the requirements: Testers require good listening and understanding capabilities to be able to communicate with the customers the application requirements.
The decision-making ability to analyze when to stop testing
Ability to work under time constraints
Ability to decide which tests to execute first
Testing the entire application using an optimized number of test cases