Two cases in .mocharc.json:
Typescript compiles, testdouble doesn't work:
"experimental-specifier-resolution=node",
"loader=ts-node/esm"
testdouble has a lengthy exception as indicated in the Git issue (same result whether
changing the order, or including or excluding experimental-specifier-resolution:
"loader=ts-node/esm",
"loader=testdouble"