content/testsuite: ensure unique content per test

stevvooe · estesp · commit c910b4705d58 · 2018-01-30T09:38:50.000-05:00
Signed-off-by: Stephen J Day &lt;stephen.day@docker.com&gt;
diff --git a/content/testsuite/testsuite.go b/content/testsuite/testsuite.go
@@ -9,6 +9,7 @@ import (
 	"math/rand"
 	"os"
 	"runtime"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -63,28 +64,28 @@ var labels = map[string]string{
 }
 
 func checkContentStoreWriter(ctx context.Context, t *testing.T, cs content.Store) {
-	c1, d1 := createContent(256, 1)
+	c1, d1 := createContent(256)
 	w1, err := cs.Writer(ctx, "c1", 0, "")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer w1.Close()
 
-	c2, d2 := createContent(256, 2)
+	c2, d2 := createContent(256)
 	w2, err := cs.Writer(ctx, "c2", int64(len(c2)), "")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer w2.Close()
 
-	c3, d3 := createContent(256, 3)
+	c3, d3 := createContent(256)
 	w3, err := cs.Writer(ctx, "c3", 0, d3)
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer w3.Close()
 
-	c4, d4 := createContent(256, 4)
+	c4, d4 := createContent(256)
 	w4, err := cs.Writer(ctx, "c4", int64(len(c4)), d4)
 	if err != nil {
 		t.Fatal(err)
@@ -163,7 +164,7 @@ func checkResumeWriter(ctx context.Context, t *testing.T, cs content.Store) {
 
 	var (
 		ref           = "cb"
-		cb, dgst      = createContent(256, 10)
+		cb, dgst      = createContent(256)
 		first, second = cb[:128], cb[128:]
 	)
 
@@ -223,7 +224,7 @@ func checkResumeWriter(ctx context.Context, t *testing.T, cs content.Store) {
 }
 
 func checkUploadStatus(ctx context.Context, t *testing.T, cs content.Store) {
-	c1, d1 := createContent(256, 17)
+	c1, d1 := createContent(256)
 
 	preStart := time.Now()
 	w1, err := cs.Writer(ctx, "c1", 256, d1)
@@ -292,7 +293,7 @@ func checkUploadStatus(ctx context.Context, t *testing.T, cs content.Store) {
 }
 
 func checkLabels(ctx context.Context, t *testing.T, cs content.Store) {
-	c1, d1 := createContent(256, 19)
+	c1, d1 := createContent(256)
 
 	w1, err := cs.Writer(ctx, "c1", 256, d1)
 	if err != nil {
@@ -365,7 +366,7 @@ func checkResume(rf func(context.Context, content.Writer, []byte, int64, int64,
 
 		for i, size := range sizes {
 			for j, tp := range truncations {
-				b, d := createContent(size, int64(i*len(truncations)+j))
+				b, d := createContent(size)
 				limit := int64(float64(size) * tp)
 				ref := fmt.Sprintf("ref-%d-%d", i, j)
 
@@ -548,7 +549,14 @@ func checkInfo(ctx context.Context, cs content.Store, d digest.Digest, expected
 	return nil
 }
 
-func createContent(size, seed int64) ([]byte, digest.Digest) {
+var contentSeed int64
+
+func createContent(size int64) ([]byte, digest.Digest) {
+	// each time we call this, we want to get a different seed, but it should
+	// be related to the intitialization order and fairly consistent between
+	// test runs. An atomic integer works just good enough for this.
+	seed := atomic.AddInt64(&contentSeed, 1)
+
 	b, err := ioutil.ReadAll(io.LimitReader(rand.New(rand.NewSource(seed)), size))
 	if err != nil {
 		panic(err)
