fix(test): stop the serve tests racing on the shared log buffer

logbuffer_test.go

@@ -0,0 +1,36 @@
+package goss
+
+import (
+	"bytes"
+	"sync"
+)
+
+// syncBuffer is a bytes.Buffer that is safe to write and read concurrently.
+//
+// The serve tests capture log output by pointing the process-wide logger at a
+// buffer with log.SetOutput. That destination is global, so a parallel test
+// still writes into whichever buffer was installed last while its owner reads
+// it — a data race on the buffer even though each test declares its own.
+// Guarding the buffer removes the race without giving up the shared logger.
+type syncBuffer struct {
+	mu  sync.Mutex
+	buf bytes.Buffer
+}
+
+func (b *syncBuffer) Write(p []byte) (int, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.buf.Write(p)
+}
+
+func (b *syncBuffer) String() string {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.buf.String()
+}
+
+func (b *syncBuffer) Reset() {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	b.buf.Reset()
+}

serve_test.go

@@ -1,7 +1,6 @@
 package goss
 
 import (
-	"bytes"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -44,7 +43,7 @@ func TestServeWithNoContentNegotiation(t *testing.T) {
 	for testName := range tests {
 		tc := tests[testName]
 		t.Run(testName, func(t *testing.T) {
-			var logOutput bytes.Buffer
+			var logOutput syncBuffer
 			log.SetOutput(&logOutput)
 
 			config, err := util.NewConfig(
@@ -158,7 +157,7 @@ func TestServeNegotiatingContent(t *testing.T) {
 	for testName := range tests {
 		tc := tests[testName]
 		t.Run(testName, func(t *testing.T) {
-			var logOutput bytes.Buffer
+			var logOutput syncBuffer
 			log.SetOutput(&logOutput)
 
 			config, err := util.NewConfig(
@@ -189,7 +188,7 @@ func TestServeNegotiatingContent(t *testing.T) {
 }
 
 func TestServeCacheWithNoContentNegotiation(t *testing.T) {
-	var logOutput bytes.Buffer
+	var logOutput syncBuffer
 	log.SetOutput(&logOutput)
 	const cache = time.Duration(time.Millisecond * 100)
 	config, err := util.NewConfig(
@@ -236,7 +235,7 @@ func TestServeCacheWithNoContentNegotiation(t *testing.T) {
 }
 
 func TestServeCacheNegotiatingContent(t *testing.T) {
-	var logOutput bytes.Buffer
+	var logOutput syncBuffer
 	log.SetOutput(&logOutput)
 	const cache = time.Duration(time.Millisecond * 100)
 	config, err := util.NewConfig(