The Swift Package Manager allows users to create standalone Swift applications and write unit tests for their codebase, with the XCTest framework available on every platform where Swift is installed. To test a new project using SPM, users can run `swift package init` to create a library or executable template, and then use commands like `swift test`, `swift test --parallel`, and `swift test --filter` to run tests in various ways. The test result output includes information on test cases, duration, and unexpected failures. To process the outcome of testing, users can use a tool called Testify, which converts test results into a JSON file. Additionally, SPM provides code coverage data, which is essential for measuring software quality and identifying areas that need improvement. Users can enable code coverage by using the `--enable-code-coverage` flag when running tests, and then display the report using tools like llvm-cov. To automate this process, users can create a shell script to figure out everything based on the current project, including finding the test executable path and displaying the coverage report.