tests: Add context cancelation (#15374)

A huge number of goroutines would build up from various monitors

When creating test filesystems provide a context so they can shut down when no longer needed.

cmd/config-migrate_test.go

@@ -18,6 +18,7 @@
 package cmd
 
 import (
+	"context"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -28,7 +29,10 @@ import (
 
 // Test if config v1 is purged
 func TestServerConfigMigrateV1(t *testing.T) {
-	objLayer, fsDir, err := prepareFS()
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	objLayer, fsDir, err := prepareFS(ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -164,6 +168,9 @@ func TestServerConfigMigrateInexistentConfig(t *testing.T) {
 
 // Test if a config migration from v2 to v33 is successfully done
 func TestServerConfigMigrateV2toV33(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
 	rootPath, err := ioutil.TempDir(globalTestTmpDir, "minio-")
 	if err != nil {
 		t.Fatal(err)
@@ -172,7 +179,7 @@ func TestServerConfigMigrateV2toV33(t *testing.T) {
 
 	globalConfigDir = &ConfigDir{path: rootPath}
 
-	objLayer, fsDir, err := prepareFS()
+	objLayer, fsDir, err := prepareFS(ctx)
 	if err != nil {
 		t.Fatal(err)
 	}