Async Test Takes Much Longer Than Actual Runtime – Why?

[94Rahul]

Hello Rustaceans! 👋

I’m currently writing a unit test for a simple async function that performs some string manipulation. When I run the function in my actual application using cargo run, it completes in about 1 second — as expected.

However, when I run the same function in a unit test (using #[tokio::test] or block_on), the test takes around 40 seconds to complete. I’m puzzled as to why there’s such a huge difference in runtime between the normal execution and the test environment.

Any advice, insight, or debugging tips would be greatly appreciated!

Thanks in advance! 🙏

[jieyouxu]

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