check: add unit tests to cover the new code, fix linter errors

pkg/storage/storage.go

@@ -727,6 +727,7 @@ func (is *ImageStore) FullBlobUpload(repo string, body io.Reader, digest string)
 	digester := sha256.New()
 	mw := io.MultiWriter(f, digester)
 	n, err := io.Copy(mw, body)
+
 	if err != nil {
 		return "", -1, err
 	}

pkg/storage/storage_test.go

@@ -58,6 +58,16 @@ func TestAPIs(t *testing.T) {
 			So(v, ShouldBeEmpty)
 		})
 
+		Convey("Full blob upload", func() {
+			body := []byte("this is a blob")
+			buf := bytes.NewBuffer(body)
+			d := godigest.FromBytes(body)
+			u, n, err := il.FullBlobUpload("test", buf, d.String())
+			So(err, ShouldBeNil)
+			So(n, ShouldEqual, len(body))
+			So(u, ShouldNotBeEmpty)
+		})
+
 		Convey("New blob upload", func() {
 			v, err := il.NewBlobUpload("test")
 			So(err, ShouldBeNil)