You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: fallback_test.go
    path of file: ./repos/gccrs/libgo/go/crypto/sha512
    
    the code of the file until where you have to start completion: // Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build ignore && s390x

package sha512

import (
	"fmt"
	"io"
	"testing"
)

// Tests the fallback code path in case the optimized asm
// implementation cannot be used.
//
    
func TestGenericPath(t *testing.T) {
	if useAsm == false {
		t.Skipf("assembly implementation unavailable")
	}
	useAsm = false
	defer func() { useAsm = true }()
	c := New()
	in := "ΑΒΓΔΕϜΖΗΘΙΚΛΜΝΞΟΠϺϘΡΣΤΥΦΧΨΩ"
	gold := "6922e319366d677f34c504af31bfcb29" +
		"e531c125ecd08679362bffbd6b6ebfb9" +
		"0dcc27dfc1f3d3b16a16c0763cf43b91" +
		"40bbf9bbb7233724e9a0c6655b185d76"
	if _, err := io.WriteString(c, in); err != nil {
		t.Fatalf("could not write to c: %v", err)
	}
	out := fmt.Sprintf("%x", c.Sum(nil))
	if out != gold {
		t.Fatalf("mismatch: got %s, wanted %s", out, gold)
	}
}