fix: Return an err no blob at a given height in case there is no blob

test/dummy.go

@@ -16,6 +16,9 @@ import (
 // DefaultMaxBlobSize is the default max blob size
 const DefaultMaxBlobSize = 64 * 64 * 482
 
+// ErrNoBlobAtHeight is returned when there is no blob at given height.
+var ErrNoBlobAtHeight = errors.New("no blob at given height")
+
 // DummyDA is a simple implementation of in-memory DA. Not production ready! Intended only for testing!
 //
 // Data is stored in a map, where key is a serialized sequence number. This key is returned as ID.
@@ -82,7 +85,10 @@ func (d *DummyDA) Get(ctx context.Context, ids []da.ID, _ da.Namespace) ([]da.Bl
 func (d *DummyDA) GetIDs(ctx context.Context, height uint64, _ da.Namespace) ([]da.ID, error) {
 	d.mu.Lock()
 	defer d.mu.Unlock()
-	kvps := d.data[height]
+	kvps, ok := d.data[height]
+	if !ok {
+		return nil, ErrNoBlobAtHeight
+	}
 	ids := make([]da.ID, len(kvps))
 	for i, kv := range kvps {
 		ids[i] = kv.key

test/test_suite.go

@@ -3,6 +3,7 @@ package test
 import (
 	"bytes"
 	"context"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -28,6 +29,9 @@ func RunDATestSuite(t *testing.T, d da.DA) {
 	t.Run("Concurrent read/write test", func(t *testing.T) {
 		ConcurrentReadWriteTest(t, d)
 	})
+	t.Run("No blobs at a given height", func(t *testing.T) {
+		NoBlobsAtHeightTest(t, d)
+	})
 }
 
 // BasicDATest tests round trip of messages to DA and back.
@@ -134,7 +138,9 @@ func ConcurrentReadWriteTest(t *testing.T, d da.DA) {
 		defer wg.Done()
 		for i := uint64(1); i <= 100; i++ {
 			_, err := d.GetIDs(ctx, i, []byte{})
-			assert.NoError(t, err)
+			if err != nil && !strings.Contains(err.Error(), ErrNoBlobAtHeight.Error()) {
+				assert.NoError(t, err)
+			}
 		}
 	}()
 
@@ -148,3 +154,12 @@ func ConcurrentReadWriteTest(t *testing.T, d da.DA) {
 
 	wg.Wait()
 }
+
+// NoBlobsAtHeightTest tests the case when there are no blobs at a given height in DA
+func NoBlobsAtHeightTest(t *testing.T, d da.DA) {
+	ctx := context.TODO()
+	// GetIDs should return ErrNoBlobAtHeight when there are no blobs at a given height
+	_, err := d.GetIDs(ctx, 999999999, []byte{})
+	assert.Error(t, err)
+	assert.ErrorContains(t, err, ErrNoBlobAtHeight.Error())
+}