cmd/go/internal/fsys: improve initOverlay test helper

1. Remove the use of fmt.Sprintf from t.Fatal.

2. Check for errors from initFromJSON.

3. Move 'overlay=0' to a separate cleanup function, for clarity.

Change-Id: I4d0daad248e8f26b6f159b4cc7e77fd60dc1ed98
Reviewed-on: https://go-review.googlesource.com/c/go/+/527700
Auto-Submit: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Kirill Kolyshkin <kolyshkin@gmail.com>
Reviewed-by: Bryan Mills <bcmills@google.com>

diff --git a/src/cmd/go/internal/fsys/fsys_test.go b/src/cmd/go/internal/fsys/fsys_test.go
index 2ab2bb2fbaecca8d6f1bbb17678badbc44b3f9bc..612c5213c1279e75224224b29c5328fdfee3c5c4 100644 (file)
--- a/src/cmd/go/internal/fsys/fsys_test.go
+++ b/src/cmd/go/internal/fsys/fsys_test.go
@@ -7,7 +7,6 @@ package fsys
 import (
        "encoding/json"
        "errors"
-       "fmt"
        "internal/testenv"
        "internal/txtar"
        "io"
@@ -38,7 +37,6 @@ func initOverlay(t *testing.T, config string) {
                t.Fatal(err)
        }
        t.Cleanup(func() {
-               overlay = nil
                if err := os.Chdir(prevwd); err != nil {
                        t.Fatal(err)
                }
@@ -57,10 +55,13 @@ func initOverlay(t *testing.T, config string) {
 
        var overlayJSON OverlayJSON
        if err := json.Unmarshal(a.Comment, &overlayJSON); err != nil {
-               t.Fatal(fmt.Errorf("parsing overlay JSON: %v", err))
+               t.Fatal("parsing overlay JSON:", err)
        }
 
-       initFromJSON(overlayJSON)
+       if err := initFromJSON(overlayJSON); err != nil {
+               t.Fatal(err)
+       }
+       t.Cleanup(func() { overlay = nil })
 }
 
 func TestIsDir(t *testing.T) {