fpc/packages/paszlib/tests/README.md

The WebAssembly version of the tczipper test reads/writes temporary files in the current directory and in the TMP directory (this is the directory returned by gettempdir).

You must pre-open these directories so the wasm environment can write in it.

Using wasmtime this can be done as follows:

wasmtime --dir=. --dir=/tmp tczipper.wasm

Similarly the testsingle test needs the same 2 directories:

wasmtime --dir=. --dir=/tmp testsingle.wasm