filetree: Marshal file and dir names to YAML

Will deal with content next.

filetree/filetree.go

@@ -14,6 +14,19 @@ type Node struct {
 	Parent   *Node       `json:"-"`
 }
 
+func (n Node) MarshalYAML() (interface{}, error) {
+	tree := map[string]interface{}{}
+	for _, child := range n.Children {
+		c, err := child.MarshalYAML()
+		if err != nil {
+			return tree, err
+		}
+		tree[child.Info.Name()] = c
+	}
+
+	return tree, nil
+}
+
 // Helper function that returns true if a path exists in excludes array
 func excluded(exclude []string, path string) bool {
 	for _, n := range exclude {

filetree/filetree_test.go

@@ -9,6 +9,7 @@ import (
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	yaml "gopkg.in/yaml.v2"
 
 	"github.com/circleci/circleci-cli/filetree"
 )
@@ -61,6 +62,18 @@ var _ = Describe("filetree", func() {
 			Expect(tree.Children[1].Children[0].Info.Name()).To(Equal("sub_dir_file"))
 			Expect(tree.Children[1].Children[0].FullPath).To(Equal(subDirFile))
 		})
+
+		It("renders to YAML", func() {
+			tree, err := filetree.NewTree(tempRoot)
+			Expect(err).ToNot(HaveOccurred())
+
+			out, err := yaml.Marshal(tree)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(out).To(MatchYAML(`root_file: {}
+sub_dir:
+  sub_dir_file: {}
+`))
+		})
 	})
 })