@tejp/testing-streams

testing-streams

Streams for test cases.

The streams read/write predefined data and errors.

API

new ChunkReader(chunks, [options])

A readable stream that produces the given chunks of data when sombody tries to read from the stream.

chunks is an array that contains data objects, but it can also contain Error instances if the stream should emit errors. Additionally chunks can contain functions that are called as callbacks and can implement more complicated custom behavior.

For each read() the stream processes the next items in chunks.

function readHandler(stream) {
    // We could push some data
    stream.push("some data");

    // We could also emit an error
    stream.emit('error', new Error("some error"));

    // If we return a truthy value, the ChunkReader immediately processes
    // the next chunk. If it's falsy ChunkReader instead waits for the
    // next read.
    return true;
}

const reader = new ChunkReader(["plain data", readHandler, new Error("a failure")])
// calls to reader.read() will return "plain data" and "some data" and then raise
// errors "some error" and "a failure".

new NullWriter()

A writable stream that accepts and ignores anything that is written to it .