package iotest

Import Path
	testing/iotest (on go.dev)

Dependency Relation
	imports 5 packages, and imported by one package

Involved Source Files

	    logger.go
	  d reader.go
		Package iotest implements Readers and Writers useful mainly for testing.

	    writer.go
Code Examples

	ErrReader
		package main
		
		import (
			"errors"
			"fmt"
			"testing/iotest"
		)
		
		func main() {
			// A reader that always returns a custom error.
			r := iotest.ErrReader(errors.New("custom error"))
			n, err := r.Read(nil)
			fmt.Printf("n:   %d\nerr: %q\n", n, err)
		
		}


Package-Level Functions (total 9)

	 func DataErrReader(r io.Reader) io.Reader
		DataErrReader changes the way errors are handled by a Reader. Normally, a
		Reader returns an error (typically EOF) from the first Read call after the
		last piece of data is read. DataErrReader wraps a Reader and changes its
		behavior so the final error is returned along with the final data, instead
		of in the first call after the final data.

	 func ErrReader(err error) io.Reader
		ErrReader returns an [io.Reader] that returns 0, err from all Read calls.

	 func HalfReader(r io.Reader) io.Reader
		HalfReader returns a Reader that implements Read
		by reading half as many requested bytes from r.

	 func NewReadLogger(prefix string, r io.Reader) io.Reader
		NewReadLogger returns a reader that behaves like r except
		that it logs (using [log.Printf]) each read to standard error,
		printing the prefix and the hexadecimal data read.

	 func NewWriteLogger(prefix string, w io.Writer) io.Writer
		NewWriteLogger returns a writer that behaves like w except
		that it logs (using [log.Printf]) each write to standard error,
		printing the prefix and the hexadecimal data written.

	 func OneByteReader(r io.Reader) io.Reader
		OneByteReader returns a Reader that implements
		each non-empty Read by reading one byte from r.

	 func TestReader(r io.Reader, content []byte) error
		TestReader tests that reading from r returns the expected file content.
		It does reads of different sizes, until EOF.
		If r implements [io.ReaderAt] or [io.Seeker], TestReader also checks
		that those operations behave as they should.
		
		If TestReader finds any misbehaviors, it returns an error reporting them.
		The error text may span multiple lines.

	 func TimeoutReader(r io.Reader) io.Reader
		TimeoutReader returns [ErrTimeout] on the second read
		with no data. Subsequent calls to read succeed.

	 func TruncateWriter(w io.Writer, n int64) io.Writer
		TruncateWriter returns a Writer that writes to w
		but stops silently after n bytes.


Package-Level Variables (only one)

	  var ErrTimeout error
		ErrTimeout is a fake timeout error.

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