diff --git a/core/coreiface/tests/api.go b/core/coreiface/tests/api.go
index ab1feff5b..23ec0612b 100644
--- a/core/coreiface/tests/api.go
+++ b/core/coreiface/tests/api.go
@@ -71,7 +71,7 @@ func TestApi(p Provider) func(t *testing.T) {
 			select {
 			case <-zeroRunning:
 			case <-time.After(time.Second):
-				t.Errorf("%d node(s) not closed", running)
+				t.Errorf("%d test swarms(s) not closed", running)
 			}
 		})
 	}
diff --git a/core/coreiface/tests/block.go b/core/coreiface/tests/block.go
index a3a5f93aa..d1117cc50 100644
--- a/core/coreiface/tests/block.go
+++ b/core/coreiface/tests/block.go
@@ -26,12 +26,12 @@ func (tp *provider) TestBlockPut(t *testing.T) {
 	defer cancel()
 	api, err := tp.makeAPI(ctx)
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	res, err := api.Block().Put(ctx, strings.NewReader(`Hello`))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	if res.Path().Cid().String() != "QmPyo15ynbVrSTVdJL9th7JysHaAbXt9dM9tXk1bMHbRtk" {
@@ -49,7 +49,7 @@ func (tp *provider) TestBlockPutFormat(t *testing.T) {
 
 	res, err := api.Block().Put(ctx, strings.NewReader(`Hello`), opt.Block.Format("cbor"))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	if res.Path().Cid().String() != "zdpuAn4amuLWo8Widi5v6VQpuo2dnpnwbVE3oB6qqs7mDSeoa" {
@@ -85,7 +85,7 @@ func (tp *provider) TestBlockGet(t *testing.T) {
 
 	res, err := api.Block().Put(ctx, strings.NewReader(`Hello`), opt.Block.Hash(mh.KECCAK_512, -1))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	r, err := api.Block().Get(ctx, res.Path())
@@ -126,7 +126,7 @@ func (tp *provider) TestBlockRm(t *testing.T) {
 
 	res, err := api.Block().Put(ctx, strings.NewReader(`Hello`))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	r, err := api.Block().Get(ctx, res.Path())
@@ -180,7 +180,7 @@ func (tp *provider) TestBlockStat(t *testing.T) {
 
 	res, err := api.Block().Put(ctx, strings.NewReader(`Hello`))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	stat, err := api.Block().Stat(ctx, res.Path())
diff --git a/core/coreiface/tests/dag.go b/core/coreiface/tests/dag.go
index 636c38699..d50263943 100644
--- a/core/coreiface/tests/dag.go
+++ b/core/coreiface/tests/dag.go
@@ -40,7 +40,7 @@ func (tp *provider) TestPut(t *testing.T) {
 
 	res, err := api.Dag().Put(ctx, strings.NewReader(`"Hello"`))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	if res.Cid().String() != "zdpuAqckYF3ToF3gcJNxPZXmnmGuXd3gxHCXhq81HGxBejEvv" {
@@ -58,7 +58,7 @@ func (tp *provider) TestPutWithHash(t *testing.T) {
 
 	res, err := api.Dag().Put(ctx, strings.NewReader(`"Hello"`), opt.Dag.Hash(mh.ID, -1))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	if res.Cid().String() != "z5hRLNd2sv4z1c" {
@@ -76,12 +76,12 @@ func (tp *provider) TestDagPath(t *testing.T) {
 
 	sub, err := api.Dag().Put(ctx, strings.NewReader(`"foo"`))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	res, err := api.Dag().Put(ctx, strings.NewReader(`{"lnk": {"/": "`+sub.Cid().String()+`"}}`))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	p, err := coreiface.ParsePath(path.Join(res.Cid().String(), "lnk"))
@@ -109,7 +109,7 @@ func (tp *provider) TestTree(t *testing.T) {
 
 	c, err := api.Dag().Put(ctx, strings.NewReader(`{"a": 123, "b": "foo", "c": {"d": 321, "e": 111}}`))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	res, err := api.Dag().Get(ctx, c)
@@ -141,7 +141,7 @@ func (tp *provider) TestBatch(t *testing.T) {
 
 	c, err := batch.Put(ctx, strings.NewReader(`"Hello"`))
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
 
 	if c.Cid().String() != "zdpuAqckYF3ToF3gcJNxPZXmnmGuXd3gxHCXhq81HGxBejEvv" {