A Test Environment Specialist or Test Environment Manager is primarily responsible for setting up, maintaining, and managing the test environments. This role ensures that the testing team has the necessary tools, software, and configurations to execute test cases effectively.

Jenkins is a powerful and widely-used open-source tool that provides continuous integration and continuous delivery facilities for software development. Its extensive plugin system and integrations allow it to fit seamlessly into a DevOps environment, enabling automatic code integration, testing, and deployment processes.

Cloud-based mobile application testing offers scalable testing environments, meaning you can expand or reduce resources as per your testing needs. This scalability ensures flexibility and cost-effectiveness, allowing teams to test on multiple devices and configurations without the need for physical infrastructure, unlike traditional labs. Moreover, cloud-based testing isn't bound by geographic locations, ensuring wider test coverage.

The Agile model of Software Development Life Cycle (SDLC) emphasizes continuous iterations of development and testing. Each iteration involves phases like requirements, design, coding, and testing.

Stress Testing involves assessing the system under extreme conditions beyond its specifications. In scenarios where there's an unexpected surge in users, like company-wide events, it's vital to determine if the software can sustain the stress or if it breaks, thus helping in predicting and preventing potential crashes.

Focusing on high-priority test cases ensures that the most crucial functionalities are tested, reducing the risk of critical defects. While allocating more resources can be helpful, it might not always be feasible. Skipping testing altogether is not recommended due to high risks. Parallelizing tasks could help but prioritizing guarantees the most important areas are covered.

UI (User Interface) changes in an application can often break test scripts, especially in automation. This is because automated tests might rely on specific elements, identifiers, or layouts on the interface. Ensuring scripts are resilient to these changes reduces maintenance efforts.

A positive test case is designed to test the application under positive conditions, and it is expected to pass. Such tests confirm that a feature or functionality works as intended when provided with valid input data.

Boundary Value Analysis is a software testing technique that involves testing at the boundaries between partitions. It focuses on the values that lie at the "edges" or boundaries of the allowed input and output ranges, as these values often have a higher likelihood of causing errors.

In resource planning, it's essential to allocate tasks based on a tester's "Expertise". By doing this, the strengths of each tester are leveraged, ensuring that the testing process is efficient and effective.

Acceptance Testing is a QA process where the software is tested to validate if it's up to the business standards and requirements. It ensures that the system complies with the requirements and validates that the right solution is provided for the end-users as specified in the contract.

Risk assessment is vital in test planning and estimation because it allows teams to identify potential challenges or threats in advance. By understanding these risks, teams can allocate appropriate resources, prioritize test scenarios that address critical functionalities, and determine the overall scope of testing to ensure that key functionalities are thoroughly tested.