better tests

hello/hello.go

@@ -2,8 +2,13 @@ package main
 
 import "fmt"
 
+const englishHelloPrefix = "Hello, "
+
 func Hello(name string) string {
-  return "Hello, " + name
+  if name == "" {
+    name = "World"
+  }
+  return englishHelloPrefix + name
 }
 
 func main() {

hello/hello_test.go

@@ -3,9 +3,20 @@ package main
 import "testing"
 
 func TestHello(t *testing.T) {
-  got := Hello("Chris")
-  want := "Hello, Chris"
+  t.Run("saying hello to people", func(t *testing.T) {
+    got := Hello("Chris")
+    want := "Hello, Chris"
+    assertCorrectMessage(t, got, want)
+  })
+  t.Run("say 'Hello, World' when an empty string is supplied", func(t *testing.T) {
+    got := Hello("")
+    want := "Hello, World"
+    assertCorrectMessage(t, got, want)
+  })
+}
 
+func assertCorrectMessage(t testing.TB, got, want string) {
+  t.Helper()
   if got != want {
     t.Errorf("got %q want %q", got, want)
   }