无法使测试套件通过 golang “sayHello() used as value”

Question

我试图让这个测试套件通过命令提示符 (hello-world_test.go)：package helloworldimport "testing"func TestHelloWorld(t *testing.T) {    output := sayHello()    if "Hello, World!" != output {        t.Fatalf("output: %s\nexpected: Hello,World!", output)    }}我的代码如下（helloworld.go）：package helloworldimport "fmt"func sayHello() {    fmt.Println("Hello, World!")}并且通过命令提示符的错误代码是：C:\Users\Troy\exercism\go\hello-world\go test -v# _/C_/Users/Troy/exercism/go/hello-world.\hello-world_test.go:6: sayHello() used as valueFAIL    _/C_/Users/Troy/exercism/go/hello-world [build failed]