protobuf.js/tests/README.md

This folder contains all the tests, one per file.

It is essential that tests only use the cross-platform API that is also available in browsers:

• Use load, not loadSync
• Use Reader.create, not BufferReader
• Use Writer.create, not BufferWriter
• It is safe to use Long, but TypeScript tests must import the type from "long"

If it's absolutely inevitable for your test case to use node-specific features, you can still use this pattern:

if (protobuf.util.isNode) {
    // node-specific tests
}

Why? Tests are run both under node.js and within all kinds of modern to ancient browsers automatically.