The testing of the JavaScript part of the Aura component can be tested in the Jest framework and the Apex controllers can be tested using test classes. The testing can be viewed in the lightning.force.com/c
/jasminetests.app URL. The page loads and runs Jasmine test and writes pass/fail information to the screen.
The Lightning test service AppExchange package is not required for testing Aura components, but for testing Lightning web components. The $T test helper object is not a valid object for testing Lightning components.

To run a subset of tests, set the Run Specified Tests test level on the DeployOptions object and pass it as an argument to the deploy() call and specify only the test classes that are required to be executed, as specifying the test method is not supported in DeployOptions. These statements are true regarding running specific tests during deployments. The Run Specified Tests test level allows the developer to choose which tests to run in production, while specifying the test method is not a valid option for the DeployOptions object.

The best practices to support UC's new package development strategy are to test developed packages in test environments before installing to production, and to consult the metadata coverage report to identify features supported by packages. Testing packages in test environments can help to ensure the quality and functionality of the packages, as well as to identify and resolve any issues or dependencies before deploying to production.
Consulting the metadata coverage report can help to determine which features can be included in packages, and which ones need to be deployed using other methods. Version control still needs to be used, as packages do not manage all the code and configuration, but only the components that are part of the package. Moving everything in the existing codebase to a single monolithic package is not a good practice, as it reduces the modularity, maintainability, and reusability of the code. It is better to create smaller packages that are focused on specific features or functionalities.

The best strategy to delete the day's test data in a partial copy sandbox every night is to execute a batch job that deletes all records created on the day. This way, you can automate the process of cleaning up the test data and avoid manual work. Manually deleting all records individually is time-consuming and error-prone.
Creating a new developer copy sandbox every night is unnecessary and wasteful, as developer copy sandboxes have limited storage and functionality. Refreshing the sandbox every night is also not feasible, as partial copy sandboxes have a refresh interval of 5 days.

Creating design standards focused on integration and providing training to all teams is the best way to address the challenges of having various integration patterns and a lack of common understanding of the integration landscape. Design standards can help to establish consistent and best practices for integrating Salesforce with other systems, such as choosing the appropriate integration style, pattern, tool, and protocol. Training can help to educate and align the teams on the design standards and the integration architecture.