Remove cd from test -cd tests/sizes.ts. because here it's meant to indicate the location of the test file, not a cd command to execute.
Add hyper link to https://mochajs.org/#exclusive-tests on how to add .only to the describe call, which can be helpful for anyone who hasn't used this feature before.
Problem
In this page: https://solana.com/developers/courses/program-optimization/program-architecture I mainly made 2 small changes:
cdfrom test -cd tests/sizes.ts. because here it's meant to indicate the location of the test file, not acdcommand to execute..onlyto thedescribecall, which can be helpful for anyone who hasn't used this feature before.