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ekingery's solution

to Hello World in the Go Track

Published at Jul 13 2018 · 0 comments
Test suite


This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

The classical introductory exercise. Just say "Hello, World!".

"Hello, World!" is the traditional first program for beginning programming in a new language or environment.

The objectives are simple:

  • Write a function that returns the string "Hello, World!".
  • Run the test suite and make sure that it succeeds.
  • Submit your solution and check it at the website.

If everything goes well, you will be ready to fetch your first real exercise.

Running the tests

To run the tests run the command go test from within the exercise directory.

If the test suite contains benchmarks, you can run these with the --bench and --benchmem flags:

go test -v --bench . --benchmem

Keep in mind that each reviewer will run benchmarks on a different machine, with different specs, so the results from these benchmark tests may vary.

Further information

For more detailed information about the Go track, including how to get help if you're having trouble, please visit the exercism.io Go language page.


This is an exercise to introduce users to using Exercism http://en.wikipedia.org/wiki/%22Hello,_world!%22_program

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


package greeting

import "testing"

// Define a function named HelloWorld that takes no arguments,
// and returns a string.
// In other words, define a function with the following signature:
// HelloWorld() string

func TestHelloWorld(t *testing.T) {
	expected := "Hello, World!"
	if observed := HelloWorld(); observed != expected {
		t.Fatalf("HelloWorld() = %v, want %v", observed, expected)

// BenchmarkHelloWorld() is a benchmarking function. These functions follow the
// form `func BenchmarkXxx(*testing.B)` and can be used to test the performance
// of your implementation. They may not be present in every exercise, but when
// they are you can run them by including the `-bench` flag with the `go test`
// command, like so: `go test -v --bench . --benchmem`
// You will see output similar to the following:
// BenchmarkHelloWorld   	2000000000	         0.46 ns/op
// This means that the loop ran 2000000000 times at a speed of 0.46 ns per loop.
// While benchmarking can be useful to compare different iterations of the same
// exercise, keep in mind that others will run the same benchmarks on different
// machines, with different specs, so the results from these benchmark tests may
// vary.
func BenchmarkHelloWorld(b *testing.B) {
	for i := 0; i < b.N; i++ {
package hello

const testVersion = 2

// Says hello
func HelloWorld(input string) string {
	if input == "" {
		input = "World"
	return "Hello, " + input + "!"

What can you learn from this solution?

A huge amount can be learned from reading other peopleโ€™s code. This is why we wanted to give exercism users the option of making their solutions public.

Here are some questions to help you reflect on this solution and learn the most from it.

  • What compromises have been made?
  • Are there new concepts here that you could read more about to improve your understanding?