testing.slide

Testing in Go
# Libraries and best practices
5 Apr 2018
Tags: go, testing, unit-testing, integration-testing

Iaroslav Ciupin
Go Developer, Ellation
iaroslav.ciupin@ellation.com
http://ellation.com

* Agenda 

- Standard library
- testify
- Testing web services
- gock
- go-sqlmock
- Integration tests

* Testing using standard library

func_test.go
.code -numbers code/func_test.go

 go test ./...
 go test ./<package_name> -run="Test.*"

: test files names .*_test.go + located in same package
: test cases are considered functions func Test.*
: run tests: all, for package, concrete functions

* github.com/stretchr/testify

github.com/stretchr/testify/assert

   assert.Equal(t, 123, 123, "they should be equal")
   assert.NoError(t, err, "no error expected")
   assert.Contains(t, "ABC", "A", "string should contain A")
   assert.Len(t, []int{1, 2}, 2, "slice should have length 2")
   assert.NotNil(t, obj, "should not be nil")
   assert.IsType(t, MyType{}, obj, "should be of type MyType")
   assert.NotPanics(t, func, "should not panic")
   and other ...

: testify - library with a bunch of testing helpers
: assert - has plenty of asserting functions with optional description

github.com/stretchr/testify/require

Same as assert, but calls `t.FailNow()` (stops test immediately)

* github.com/stretchr/testify/assert

.code -numbers code/assert_test.go

: create assert/require objects for re-use
: more readable tests

* Data-driven testing

.code -numbers code/data_test.go /^func Test/,/^}/

	--- FAIL: TestF (0.00s)
		data_test.go:18:
				Error Trace:	data_test.go:18
				Error:      	Not equal:
				            	expected: 44
				            	actual  : 43
				Test:       	TestF
				Messages:   	input 42
	FAIL

: No built-in or 3-rd party support for data-driven testing :(
: Actually, you don't even need it!
: Have to use good old for-loop
: Good practice to mark test case in test description
: Lesson learnt: always think about failed runs, not only success runs

* Benchmarking using standard library

.code -numbers code/bench_test.go /^func Bench/,/^}/

 go test -bench=Benchmark.* -benchmem -benchtime=10s

	goos: darwin
	goarch: amd64
	pkg: github.com/iaroslav-ciupin/testing-in-go/code
	BenchmarkAnswer-8   	200000000	        76.9 ns/op	     352 B/op	       1 allocs/op
	PASS
	ok  	github.com/iaroslav-ciupin/testing-in-go/code	23.039s

* Coverage?

TODO

* github.com/stretchr/testify/mock

TODO 

: mocking dependencies
: setting/asserting expectations

* github.com/stretchr/testify/suite

TODO 

: structuring more complex testing logic
: beforeAll, beforeEvery, afterAll, afterEvery
: built-in assertions

* Simple web server

.image testing-in-go.png

* httptest request and server

TODO

* github.com/h2non/gock

TODO

- easy HTTP request/response mocking

* github.com/DATA-DOG/go-sqlmock

: NOT AN IN-MEMORY DATABASE!
: matches SQL regex
: network/database error testing

* integration testing

TODO
No library/framework :(