This fixes occurences of a loop variable being captured in parallel tests. With the previous code, only the last test case is actually exercised. To work around this problem, we create a local copy of the range variable before the parallel test, as suggested in the documentation for the `testing` package: https://pkg.go.dev/testing#hdr-Subtests_and_Sub_benchmarks Issues were found automatically using the `loopvarcapture` linter.