diff --git a/ipld-importer/import.go b/ipld-importer/import.go
index bb407310..47154c76 100644
--- a/ipld-importer/import.go
+++ b/ipld-importer/import.go
@@ -33,7 +33,6 @@ func ToPrint(f files.File) error {
 		} else if err != nil {
 			return err
 		}
-
 		if err := fileAdder.AddFile(file); err != nil {
 			return err
 		}
@@ -51,16 +50,16 @@ func ToPrint(f files.File) error {
 
 // ToChannel imports file to ipfs ipld nodes, outputting nodes on the
 // provided channel
-func ToChannel(f files.File, ctx context.Context) <-chan *ipld.Node {
+func ToChannel(f files.File, ctx context.Context) (<-chan *ipld.Node, error) {
 	outChan := make(chan *ipld.Node)
 	dserv := &outDAGService{
-		membership: make(map[string]bool),
+		membership: make(map[string]struct{}),
 		outChan:    outChan,
 	}
 
 	fileAdder, err := coreunix.NewAdder(ctx, nil, nil, dserv)
 	if err != nil {
-		return err
+		return outChan, err
 	}
 	fileAdder.Pin = false
 
@@ -72,18 +71,22 @@ func ToChannel(f files.File, ctx context.Context) <-chan *ipld.Node {
 			if err == io.EOF {
 				break
 			} else if err != nil {
-				return err
+				return
+			}
+			select {
+			case <-ctx.Done():
+				return
+			default:
 			}
-
 			if err := fileAdder.AddFile(file); err != nil {
-				return err
+				return
 			}
 		}
 
 		_, err = fileAdder.Finalize()
 		if !strings.Contains(err.Error(), "dagservice: block not found") {
-			return err
+			return
 		}
 	}()
-	return outChan
+	return outChan, nil
 }
diff --git a/ipld-importer/import_test.go b/ipld-importer/import_test.go
index d3104516..0bc560b5 100644
--- a/ipld-importer/import_test.go
+++ b/ipld-importer/import_test.go
@@ -8,7 +8,6 @@ import (
 	"testing"
 
 	"github.com/ipfs/go-ipfs-cmdkit/files"
-	ipld "github.com/ipfs/go-ipld-format"
 )
 
 const testDir = "testingData"
@@ -39,7 +38,7 @@ func TestToPrint(t *testing.T) {
 	}
 }
 
-var orderedCids = [18]string{"QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn",
+var cids = [18]string{"QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn",
 	"Qmbp4C4KkyjVzTpZ327Ub555FEHizhJS4M17f2zCCrQMAz",
 	"QmYz38urZ99eVCxSccM63bGtDv54UWtBDWJdTxGch23khA",
 	"QmUwG2mfhhfBEzVtvyEvva1kc8kU4CrXphdMCdAiFNWdxy",
@@ -49,10 +48,10 @@ var orderedCids = [18]string{"QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn",
 	"QmcUBApwNSDg2Q2J4NXzks1HewVGFohNpPyEud7bZfo5tE",
 	"QmaKaB735eydQwnaJNuYbXRU1gVb4MJdzHp1rpUZJN67G6",
 	"QmQ6n82dRtEJVHMDLW5BSrJ6bRDXkFXj2i7Vjxy4B2PH82",
-	"QmbDaWrwxk93RfWSBL8ajTproNKbE2EghBLSk8199EBm1m",
-	"QmXDmRPxV9KWYLhN7bqGn143GgiNxhy9Hqc3ZPJW63xgok",
 	"QmPZLJ3CZYgxH4K1w5jdbAdxJynXn5TCB4kHy7u8uHC3fy",
 	"QmUqmcdJJodX7mPoUv9u71HoNAiegBCiCqdUZd5ZrCyLbs",
+	"QmbDaWrwxk93RfWSBL8ajTproNKbE2EghBLSk8199EBm1m",
+	"QmXDmRPxV9KWYLhN7bqGn143GgiNxhy9Hqc3ZPJW63xgok",
 	"QmaytnNarHzDp1ipGyC7zd7Hw2AePmtSpLLaygQ2e9Yvqe",
 	"QmZwab9h6ADw3tv8pzXVF2yndgJpTWKrrMjJQqRkgYmCRH",
 	"QmaNfMZDZjfqjHrFCc6tZwmkqbXs1fnY9AXZ81WUztFeXm",
@@ -65,19 +64,35 @@ func TestToChannel(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	outChan := make(chan *ipld.Node)
-	go func() {
-		i := 0
-		for node := range outChan {
-			cid := (*node).String()
-			if cid != orderedCids[i] {
-				t.Error("unexpected cid: %s instead of %s", cid, orderedCids[i])
-			}
-			i += 1
-		}
-	}()
-	err = ToChannel(file, outChan, context.Background())
+	outChan, err := ToChannel(file, context.Background())
 	if err != nil {
 		t.Fatal(err)
 	}
+
+	check := make(map[string]struct{})
+	for node := range outChan {
+		cid := (*node).String()
+		if _, ok := check[cid]; ok {
+			t.Fatalf("Duplicate cid %s", cid)
+		}
+		check[cid] = struct{}{}
+	}
+	if len(check) != len(cids) {
+		t.Fatalf("Witnessed cids: %v\nExpected cids: %v", check, cids)
+	}
+	cidsS := cids[:]
+	for cid := range check {
+		if !contains(cidsS, cid) {
+			t.Fatalf("Unexpected cid: %s", cid)
+		}
+	}
+}
+
+func contains(slice []string, s string) bool {
+	for _, a := range slice {
+		if a == s {
+			return true
+		}
+	}
+	return false
 }
diff --git a/ipld-importer/outgoing-dagservice.go b/ipld-importer/outgoing-dagservice.go
index 4c4f60e0..4f44ab37 100644
--- a/ipld-importer/outgoing-dagservice.go
+++ b/ipld-importer/outgoing-dagservice.go
@@ -13,7 +13,7 @@ var errUninit = errors.New("DAGService output channel uninitialized")
 
 // outDAGService will "add" a node by sending through the outChan
 type outDAGService struct {
-	membership map[string]bool
+	membership map[string]struct{}
 	outChan    chan<- *ipld.Node
 }
 
@@ -24,11 +24,9 @@ func (ods *outDAGService) Get(ctx context.Context, key *cid.Cid) (ipld.Node, err
 
 // GetMany returns an output channel that always emits an error
 func (ods *outDAGService) GetMany(ctx context.Context, keys []*cid.Cid) <-chan *ipld.NodeOption {
-	out := make(chan *ipld.NodeOption, len(keys))
-	go func() {
-		out <- &ipld.NodeOption{Err: fmt.Errorf("failed to fetch all nodes")}
-		return
-	}()
+	out := make(chan *ipld.NodeOption, 1)
+	out <- &ipld.NodeOption{Err: fmt.Errorf("failed to fetch all nodes")}
+	close(out)
 	return out
 }
 
@@ -39,7 +37,7 @@ func (ods *outDAGService) Add(ctx context.Context, node ipld.Node) error {
 	if ok { // already added don't add again
 		return nil
 	}
-	ods.membership[id] = true
+	ods.membership[id] = struct{}{}
 
 	// Send node on output channel
 	if ods.outChan == nil {