Writing, building, installing, and testing Go code

gistfile1.sh

# from https://www.youtube.com/watch?v=XCsL89YtqCs
mkdir gocode
export GOPATH=$HOME/gocode
cd gocode
mkdir -p src/github.com/xd547
mkdir hello
cd hello
# create hello.go 
# see hello.go below
go install
ls ~/gocode/bin
# hello
~/gocode/bin/hello
# Hello, new gopher!
cd ..
mkdir string
cd string
# create string.go
# see string.go below
go build
go install
ls ~/gocode/pkg/darwin_amd64/github.com/xd547
# string.a
cd ../hello
# edit hello.go
# see hello_new.go
go install
hello
# !rehpog wen ,olleH
cd ../string
# edit create string_test.go
# see string_test.go below
go test
# --- FAIL: Test (0.00 seconds)
# 	string_test.go:16: Reverse("Hello, 世界") == "\x8c\x95疸\xe4 ,olleH", want "界世 ,olleH"
# FAIL
# exit status 1
# FAIL	github.com/xd547/string	0.009s
#
# edit string.go
# see string_new.go
go test
# PASS
# ok  	github.com/xd547/string	0.008s

hello.go

package main

import "fmt"

func main() {
    fmt.Println("Hello, new gopher!");
}

hello_new.go

package main

import (
    "fmt"
    "github.com/xd547/string"
)

func main() {
    fmt.Println(string.Reverse("Hello, new gopher!"));
}

string.go

package string

func Reverse(s string) string {
    b := []byte(s)
    for i := 0; i < len(b)/2; i++ {
        j := len(b)-i-1
        b[i], b[j] = b[j], b[i]
    }

    return string(b)
}

string_new.go

package string

func Reverse(s string) string {
    b := []rune(s)
    for i := 0; i < len(b)/2; i++ {
        j := len(b)-i-1
        b[i], b[j] = b[j], b[i]
    }

    return string(b)
}

string_test.go

package string

import "testing"

func Test(t *testing.T) {
    var tests = []struct {
        s, want string
    }{
        {"Backward", "drawkcaB"},
        {"Hello, 世界", "界世 ,olleH"},
        {"", ""},
    }
    for _, c := range tests {
        got := Reverse(c.s)
        if got != c.want {
          t.Errorf("Reverse(%q) == %q, want %q", c.s, got, c.want)
        }
    }
}