tests: Implemented more tests for fs-v1*.go (#2686)

cmd/naughty-disk_test.go

@@ -16,7 +16,10 @@
 
 package cmd
 
-import "github.com/minio/minio/pkg/disk"
+import (
+	"github.com/minio/minio/pkg/disk"
+	"sync"
+)
 
 // naughtyDisk wraps a POSIX disk and returns programmed errors
 // specified by the developer. The purpose is to simulate errors
@@ -31,6 +34,8 @@ type naughtyDisk struct {
 	defaultErr error
 	// The current API call number
 	callNR int
+	// Data protection
+	mu sync.Mutex
 }
 
 func newNaughtyDisk(d *posix, errs map[int]error, defaultErr error) *naughtyDisk {
@@ -38,6 +43,8 @@ func newNaughtyDisk(d *posix, errs map[int]error, defaultErr error) *naughtyDisk
 }
 
 func (d *naughtyDisk) calcError() (err error) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
 	d.callNR++
 	if err, ok := d.errors[d.callNR]; ok {
 		return err