Package: testing/iotest

package iotest Import Path testing/iotest (on go.dev) Dependency Relation imports 5 packages, and imported by 0 packages

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 Type Names (total 9, none are exported)

/* sort exporteds by: alphabet | popularity */

/* 9 unexporteds ... *//* 9 unexporteds: */

Package-Level Functions (total 9, all are exported)

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, which is exported)

var ErrTimeout error ErrTimeout is a fake timeout error.