Move to subfolder

hello/go.mod

@@ -0,0 +1,3 @@
+module go_with_tests
+
+go 1.26.1

hello/hello.go

@@ -0,0 +1,36 @@
+package main
+
+import "fmt"
+
+const (
+	spanish            = "Spanish"
+	french             = "French"
+	englishHelloPrefix = "Hello, "
+	spanishHelloPrefix = "Hola, "
+	frenchHelloPrefix  = "Bonjour, "
+)
+
+func Hello(name, language string) string {
+	if name == "" {
+		name = "World"
+	}
+
+	prefix := greetingPrefix(language)
+	return prefix + name
+}
+
+func greetingPrefix(language string) (prefix string) {
+	switch language {
+	case french:
+		prefix = frenchHelloPrefix
+	case spanish:
+		prefix = spanishHelloPrefix
+	default:
+		prefix = englishHelloPrefix
+	}
+	return
+}
+
+func main() {
+	fmt.Println(Hello("Hoborg", ""))
+}

hello/hello_test.go

@@ -0,0 +1,33 @@
+package main
+
+import "testing"
+
+func TestHello(t *testing.T) {
+	t.Run("saying hello to people", func(t *testing.T) {
+		got := Hello("Hoborg", "")
+		want := "Hello, Hoborg"
+		assertMessage(t, got, want)
+	})
+	t.Run("say 'Hello, World' when an empty string is given", func(t *testing.T) {
+		got := Hello("", "")
+		want := "Hello, World"
+		assertMessage(t, got, want)
+	})
+	t.Run("hello in Spanish", func(t *testing.T) {
+		got := Hello("Elodie", "Spanish")
+		want := "Hola, Elodie"
+		assertMessage(t, got, want)
+	})
+	t.Run("hello in French", func(t *testing.T) {
+		got := Hello("Émile", "French")
+		want := "Bonjour, Émile"
+		assertMessage(t, got, want)
+	})
+}
+
+func assertMessage(t testing.TB, got, want string) {
+	t.Helper()
+	if got != want {
+		t.Errorf("got %q want %q", got, want)
+	}
+}