Testing Wasm parts:

# 1. install lib
go install github.com/agnivade/wasmbrowsertest@latest

# 2.A. rename so that go test finds it automatically
mv "$(go env GOPATH)/bin/wasmbrowsertest" "$(go env GOPATH)/bin/go_js_wasm_exec"
# then run like so:
GOOS=js GOARCH=wasm go test ./filesystem

# 2.B. or run the tests with a flag
GOOS=js GOARCH=wasm go test -exec /Users/firu/go/bin/wasmbrowsertest ./filesystem

More info here: https://github.com/agnivade/wasmbrowsertest