go 单元测试testify

testify介绍

testify用go实现的一个assert风格的测试框架，这个包提供了我们需要的断言的功能,提供了非常丰富的断言方法。

提供了测试suite、断言、mock三种功能。

官方文档：https://godoc.org/github.com/stretchr/testify

安装：

go get -u -v github.com/stretchr/testify

testify断言

有两种断言方式，区别是require的断言失败会直接导致程序结束，而assert虽然也标记为此case失败，但程序不会退出，而是继续往下执行。

1. assert
2. require

import (
    "github.com/stretchr/testify/assert"
    "testing"
)

//单元测试函数
func TestAddNum(t *testing.T) {
    result :=  addNum(100)
    assert.Equal(t, 5050, result)
}

功能代码如下：

func addNum(n int) (result int) {
    for i := 0; i <= n; i++ {
        result = result + i
    }
    return result 
}　

更多断言类型：

https://godoc.org/github.com/stretchr/testify/assert

https://godoc.org/github.com/stretchr/testify/require

testify suite

package untest

// Basic imports
import (
    "testing"
    "github.com/stretchr/testify/assert"
    "github.com/stretchr/testify/suite"
)

type ExampleTestSuite struct {
    suite.Suite
    VariableThatShouldStartAtFive int
}

// 每个测试用例执行前都会调用
func (suite *ExampleTestSuite) SetupTest() {
    suite.VariableThatShouldStartAtFive = 5
}

//一个测试用例
func (suite *ExampleTestSuite) TestExample() {
    assert.Equal(suite.T(), 5, suite.VariableThatShouldStartAtFive)
    suite.Equal(5, suite.VariableThatShouldStartAtFive)
}

// In order for 'go test' to run this suite, we need to create
// a normal test function and pass our suite to suite.Run
func TestExampleTestSuite(t *testing.T) {
    suite.Run(t, new(ExampleTestSuite))
}

// 每个测试用例执行后都会调用
func (suite *ExampleTestSuite) TearDownTest() {

}

Table Driven Test

通过构造结构体切片进行table driven test，这里传入常规参数的情况，代码实现如下：

func TestSqrt(t *testing.T) {
  testcases := []struct {
    desc   string
    input  float64
    expect float64
  }{
    {
      desc:   "zero",
      input:  0,
      expect: 0,
    },
    {
      desc:   "one",
      input:  1,
      expect: 1,
    },
    {
      desc: "a very small rational number",
      input: 0.00000000000000000000000001,
      expect: 0.0,
    },
    {
      desc:   "rational number result: 2.56",
      input:  2.56,
      expect: 1.6,
    },
    {
      desc:   "irrational number result: 2",
      input:  2,
      expect: 1.414213562,
    },
  }

  for _, ts := range testcases {
    got := Sqrt(ts.input)
    erro := got - ts.expect
    require.True(t, erro < 0.000000001 && erro > -0.000000001, ts.desc)
  }
}

功能代码如下：

// Sqrt calculate the square root of a non-negative float64 
// number with max error of 10^-9. For simplicity, we don't 
// discard the part with is smaller than 10^-9.
func Sqrt(x float64) float64 {
  if x < 0 {
    panic("cannot be negative")
  }

  if x == 0 {
    return 0
  }

  a := x / 2
  b := (a + 2) / 2
  erro := a - b
  for erro >= 0.000000001 || erro <= -0.000000001 {
    a = b
    b = (b + x/b) / 2
    erro = a - b
  }

  return b
}