helpers

README

LaunchDarkly Go Test Helpers

This project centralizes some test support code that is used by LaunchDarkly's Go SDK and related components, and that may be useful in other Go projects.

While this code may be useful in other projects, it is primarily geared toward LaunchDarkly's own development needs and is not meant to provide a large general-purpose framework. It is meant for unit test code and should not be used as a runtime dependency.

This version of the project requires Go 1.18 or higher.

Contents

The main package provides general-purpose helper functions.

Subpackage httphelpers provides convenience wrappers for using net/http and net/http/httptest in test code.

Subpackage jsonhelpers provides functions for manipulating JSON.

Subpackage matchers contains a test assertion API with combinators.

Subpackage testbox provides the ability to write tests-of-tests within the Go testing framework.

Usage

Import any of these packages in your test code:

import (
    "github.com/launchdarkly/go-test-helpers/v3"
    "github.com/launchdarkly/go-test-helpers/v3/httphelpers"
    "github.com/launchdarkly/go-test-helpers/v3/jsonhelpers"
    "github.com/launchdarkly/go-test-helpers/v3/ldservices"
    "github.com/launchdarkly/go-test-helpers/v3/testbox"
)

Breaking changes will only be made in a new major version. It is advisable to use a dependency manager to pin these dependencies to a module version or a major version branch.

Contributing

We encourage pull requests and other contributions from the community. Check out our contributing guidelines for instructions on how to contribute to this project.

About LaunchDarkly

• LaunchDarkly is a continuous delivery platform that provides feature flags as a service and allows developers to iterate quickly and safely. We allow you to easily flag your features and manage them from the LaunchDarkly dashboard. With LaunchDarkly, you can:
  • Roll out a new feature to a subset of your users (like a group of users who opt-in to a beta tester group), gathering feedback and bug reports from real-world use cases.
  • Gradually roll out a feature to an increasing percentage of users, and track the effect that the feature has on key metrics (for instance, how likely is a user to complete a purchase if they have feature A versus feature B?).
  • Turn off a feature that you realize is causing performance problems in production, without needing to re-deploy, or even restart the application with a changed configuration file.
  • Grant access to certain features based on user attributes, like payment plan (eg: users on the ‘gold’ plan get access to more features than users in the ‘silver’ plan). Disable parts of your application to facilitate maintenance, without taking everything offline.
• LaunchDarkly provides feature flag SDKs for a wide variety of languages and technologies. Check out our documentation for a complete list.
• Explore LaunchDarkly
  • launchdarkly.com for more information
  • docs.launchdarkly.com for our documentation and SDK reference guides
  • apidocs.launchdarkly.com for our API documentation
  • blog.launchdarkly.com for the latest product updates
  • Feature Flagging Guide for best practices and strategies

Documentation

Overview

Package helpers (github.com/launchdarkly/go-test-helpers) contains miscellaneous convenience functions for use in test code.

Index

• func AsPointer[V any](v V) *V
• func AssertChannelClosed[V any](t assert.TestingT, ch <-chan V, timeout time.Duration, ...) bool
• func AssertChannelNotClosed[V any](t assert.TestingT, ch <-chan V, timeout time.Duration, ...) bool
• func AssertNoMoreValues[V any](t assert.TestingT, ch <-chan V, timeout time.Duration, ...) bool
• func FilePathExists(path string) bool
• func ReadWithTimeout(r io.Reader, n int, timeout time.Duration) []byte
• func RequireValue[V any](t require.TestingT, ch <-chan V, timeout time.Duration, ...) V
• func TryReceive[V any](ch <-chan V, timeout time.Duration) (V, bool, bool)
• func WithCloser(closeableObject io.Closer, action func())
• func WithTempDir(f func(path string))
• func WithTempFile(f func(filePath string))
• func WithTempFileData(data []byte, f func(filePath string))

Functions

func AsPointer

func AsPointer[V any](v V) *V

AsPointer returns a pointer to a copy of a value.

func AssertChannelClosed

func AssertChannelClosed[V any](
	t assert.TestingT,
	ch <-chan V,
	timeout time.Duration,
	customMessageAndArgs ...any,
) bool

AssertChannelClosed asserts that the channel is closed within the timeout, sending no values.

func AssertChannelNotClosed

func AssertChannelNotClosed[V any](
	t assert.TestingT,
	ch <-chan V,
	timeout time.Duration,
	customMessageAndArgs ...any,
) bool

AssertChannelNotClosed asserts that the channel is not closed within the timeout, consuming any values that may be sent during that time.

func AssertNoMoreValues

func AssertNoMoreValues[V any](
	t assert.TestingT,
	ch <-chan V,
	timeout time.Duration,
	customMessageAndArgs ...any,
) bool

AssertNoMoreValues asserts that no value is available from the channel within the timeout, but that the channel was not closed.

func FilePathExists

func FilePathExists(path string) bool

FilePathExists is simply a shortcut for using os.Stat to check for a file's or directory's existence.

func ReadWithTimeout

func ReadWithTimeout(r io.Reader, n int, timeout time.Duration) []byte

ReadWithTimeout reads data until it gets the desired number of bytes or times out.

This is an inefficient implementation that should only be used in tests.

func RequireValue

func RequireValue[V any](t require.TestingT, ch <-chan V, timeout time.Duration, customMessageAndArgs ...any) V

RequireValue returns the next value from the channel, or forces an immediate test failure and exit if the timeout expires first.

func TryReceive

func TryReceive[V any](ch <-chan V, timeout time.Duration) (V, bool, bool)

TryReceive waits for a value from the channel and returns (value, true, false) if successful; (<empty>, false, false) if the timeout expired first; or (<empty>, false, true) if the channel was closed.

func WithCloser

func WithCloser(closeableObject io.Closer, action func())

WithCloser executes a function and ensures that the given object's Close() method is always called afterward.

This is simply a way to get more specific control over an object's lifetime than using defer. A test function may wish to ensure that an object is closed before some subsequent actions are taken, rather than at the end of the entire test.

If closing the object fails, an error is logged.

func WithTempDir

func WithTempDir(f func(path string))

WithTempDir creates a temporary directory, calls the function with its path, then removes it.

func WithTempFile

func WithTempFile(f func(filePath string))

WithTempFile creates a temporary file, passes its name to the given function, then ensures that the file is deleted.

If for any reason it is not possible to create the file, a panic is raised since the test code cannot continue.

If deletion of the file fails (assuming it has not already been deleted) then an error is logged, but there is no panic.

helpers.WithTempFile(func(path string) {
	DoSomethingWithTempFile(path)
}) // the file is deleted at the end of this block

func WithTempFileData

func WithTempFileData(data []byte, f func(filePath string))

WithTempFileData is identical to WithTempFile except that it prepopulates the file with the specified data.