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package poll

import ""

Package poll provides tools for testing asynchronous code.



Package Files

check.go poll.go

func WaitOn Uses

func WaitOn(t TestingT, check Check, pollOps ...SettingOp)

WaitOn a condition or until a timeout. Poll by calling check and exit when check returns a done Result. To fail a test and exit polling with an error return a error result.


desired := 10

check := func(t poll.LogT) poll.Result {
    actual, err := numOfProcesses()
    if err != nil {
        return poll.Error(errors.Wrap(err, "failed to get number of processes"))
    if actual == desired {
        return poll.Success()
    t.Logf("waiting on process count to be %d...", desired)
    return poll.Continue("number of processes is %d, not %d", actual, desired)

poll.WaitOn(t, check)

type Check Uses

type Check func(t LogT) Result

Check is a function which will be used as check for the WaitOn method.

func Connection Uses

func Connection(network, address string) Check

Connection try to open a connection to the address on the named network. See net.Dial for a description of the network and address parameters.

func FileExists Uses

func FileExists(path string) Check

FileExists looks on filesystem and check that path exists.

type LogT Uses

type LogT interface {
    Log(args ...interface{})
    Logf(format string, args ...interface{})

LogT is a logging interface that is passed to the WaitOn check function

type Result Uses

type Result interface {
    // Error indicates that the check failed and polling should stop, and the
    // the has failed
    Error() error
    // Done indicates that polling should stop, and the test should proceed
    Done() bool
    // Message provides the most recent state when polling has not completed
    Message() string

Result of a check performed by WaitOn

func Continue Uses

func Continue(message string, args ...interface{}) Result

Continue returns a Result that indicates to WaitOn that it should continue polling. The message text will be used as the failure message if the timeout is reached.

func Error Uses

func Error(err error) Result

Error returns a Result that indicates to WaitOn that it should fail the test and stop polling.

func Success Uses

func Success() Result

Success returns a Result where Done() returns true, which indicates to WaitOn that it should stop polling and exit without an error.

type SettingOp Uses

type SettingOp func(config *Settings)

SettingOp is a function which accepts and modifies Settings


check := func(t poll.LogT) poll.Result {
    if isDesiredState() {
        return poll.Success()
    return poll.Continue("state is: %s", getState())
poll.WaitOn(t, check, poll.WithTimeout(30*time.Second), poll.WithDelay(15*time.Millisecond))

func WithDelay Uses

func WithDelay(delay time.Duration) SettingOp

WithDelay sets the delay to wait between polls

func WithTimeout Uses

func WithTimeout(timeout time.Duration) SettingOp

WithTimeout sets the timeout

type Settings Uses

type Settings struct {
    // Timeout is the maximum time to wait for the condition. Defaults to 10s.
    Timeout time.Duration
    // Delay is the time to sleep between checking the condition. Defaults to
    // 100ms.
    Delay time.Duration

Settings are used to configure the behaviour of WaitOn

type TestingT Uses

type TestingT interface {
    Fatalf(format string, args ...interface{})

TestingT is the subset of testing.T used by WaitOn

Package poll imports 4 packages (graph) and is imported by 5 packages. Updated 2018-11-23. Refresh now. Tools for package owners.