// combination.go
package hmath
func combination(m, n int) int {if n > m-n {n = m - n}c := 1for i := 0; i < n; i++ {c *= m - ic /= i + 1}return c
}

// combination_test.go
package hmath
import ("math/rand""testing"
)
// 单元测试
// 测试全局函数，以TestFunction命名
// 测试类成员函数，以TestClass_Function命名
func TestCombination(t *testing.T) {// 这里定义一个临时的结构体来存储测试case的参数以及期望的返回值for _, unit := range []struct {m        intn        intexpected int}{{1, 0, 1},{4, 1, 4},{4, 2, 6},{4, 3, 4},{4, 4, 1},{10, 1, 10},{10, 3, 120},{10, 7, 120},} {// 调用排列组合函数，与期望的结果比对，如果不一致输出错误if actually := combination(unit.m, unit.n); actually != unit.expected {t.Errorf("combination: [%v], actually: [%v]", unit, actually)}}
}
// 性能测试
func BenchmarkCombination(b *testing.B) {// b.N会根据函数的运行时间取一个合适的值for i := 0; i < b.N; i++ {combination(i+1, rand.Intn(i+1))}
}
// 并发性能测试
func BenchmarkCombinationParallel(b *testing.B) {// 测试一个对象或者函数在多线程的场景下面是否安全b.RunParallel(func(pb *testing.PB) {for pb.Next() {m := rand.Intn(100) + 1n := rand.Intn(m)combination(m, n)}})
}

go test combination_test.go combination.go           # 单元测试
go test --cover combination_test.go combination.go   # 单元测试覆盖率
go test -bench=. combination_test.go combination.go  # 性能测试

func TestMain(m *testing.M) {// setup code...os.Exit(m.Run())// teardown code...
}

func TestMain(m *testing.M) {// setup code...os.Exit(m.Run())// teardown code...
}

go get github.com/smartystreets/goconvey

package package_name
import ("testing". "github.com/smartystreets/goconvey/convey"
)
func TestIntegerStuff(t *testing.T) {Convey("Given some integer with a starting value", t, func() {x := 1Convey("When the integer is incremented", func() {x++Convey("The value should be greater by one", func() {So(x, ShouldEqual, 2)})})})
}