Recommended way to measure time in Swift?

[Jens]

It depends on what you mean by simple. I'd say using XCTest APIs is not as simple as:

1. Write/download/copy-paste a single source file (command line) program
2. Compile (from command line according to instructions within the file)
3. Run

And XCTest is macOS (and Xcode?) only.

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Also, according to my experience, testing for performance will almost always mean bumping into various context dependent optimizer glitches etc, and therefore it's important to be able to measure and profile some piece of code in many different contexts. XCTest forces your code into a specific context and is a lot of boilerplate.

@Jens

Note also that these issues are impossible to represent/test/benchmark in eg XCTest and The Swift Benchmarking Suite. Why? Because the issues are all about context , and they are interacting in various funny ways as shown by eg the string-interpolation-trick working in reverse or not depending on whether base was declared in top-level or not. XCTest and The Swift Benchmarking Suite forces some layer(s) of context on the tested code, and thus their harness becomes part of the tested code.