diff --git a/tree_handler_programmably_walk_test.go b/tree_handler_programmably_walk_test.go
new file mode 100644
index 0000000..d346d80
--- /dev/null
+++ b/tree_handler_programmably_walk_test.go
@@ -0,0 +1,80 @@
+package gtree_test
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/ddddddO/gtree"
+	tu "github.com/ddddddO/gtree/testutil"
+)
+
+// TODO: 何パターンかのcallbackを用意してWalkerNode用メソッドのテストもしたい
+func TestWalkProgrammably(t *testing.T) {
+	tests := []struct {
+		name    string
+		root    *gtree.Node
+		options []gtree.Option
+		out     out
+	}{
+		{
+			name: "case(succeeded)",
+			root: tu.PrepareMultiNode(),
+			options: []gtree.Option{
+				gtree.WithBranchFormatIntermedialNode("+--", ":   "),
+				gtree.WithBranchFormatLastNode("+--", "    "),
+			},
+			out: out{
+				output: strings.TrimLeft(`
+root1
++-- child 1
+:   +-- child 2
+:       +-- child 3
+:       +-- child 4
+:           +-- child 5
+:           +-- child 6
+:               +-- child 7
++-- child 8
+`, "\n"),
+				err: nil,
+			},
+		},
+		{
+			name:    "case(succeeded/massive)",
+			root:    tu.Prepare(),
+			options: []gtree.Option{gtree.WithMassive(nil)},
+			out: out{
+				output: strings.TrimLeft(`
+root
+└── child 1
+    └── child 2
+`, "\n"),
+				err: nil,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			buf := &bytes.Buffer{}
+			callback := func(wn *gtree.WalkerNode) error {
+				fmt.Fprintln(buf, wn.Row())
+				return nil
+			}
+			gotErr := gtree.WalkProgrammably(tt.root, callback, tt.options...)
+			if gotErr != nil || tt.out.err != nil {
+				if gotErr.Error() != tt.out.err.Error() {
+					t.Errorf("\ngotErr: \n%s\nwantErr: \n%s", gotErr, tt.out.err.Error())
+				}
+			}
+			got := buf.String()
+			if got != tt.out.output {
+				t.Errorf("\ngot: \n%s\nwant: \n%s", got, tt.out.output)
+			}
+		})
+	}
+}
diff --git a/tree_handler_walk_test.go b/tree_handler_walk_test.go
new file mode 100644
index 0000000..9538164
--- /dev/null
+++ b/tree_handler_walk_test.go
@@ -0,0 +1,96 @@
+package gtree_test
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/ddddddO/gtree"
+)
+
+// TODO: 何パターンかのcallbackを用意してWalkerNode用メソッドのテストもしたい
+func TestWalk(t *testing.T) {
+	tests := []struct {
+		name string
+		in   in
+		out  out
+	}{
+		{
+			name: "case(succeeded)",
+			in: in{
+				input: strings.NewReader(strings.TrimSpace(`
+- a
+	- i
+		- u
+			- k
+	- kk
+		- t
+- e
+	- o
+		- g`)),
+			},
+			out: out{
+				output: strings.TrimLeft(`
+a
+├── i
+│   └── u
+│       └── k
+└── kk
+    └── t
+e
+└── o
+    └── g
+`, "\n"),
+				err: nil,
+			},
+		},
+		{
+			name: "case(succeeded/change branch)",
+			in: in{
+				input: strings.NewReader(strings.TrimSpace(`
+- a
+	- i
+		- u
+			- k
+	- kk
+		- t`)),
+				options: []gtree.Option{gtree.WithBranchFormatIntermedialNode("+--", ":   "), gtree.WithBranchFormatLastNode("+--", "    ")},
+			},
+			out: out{
+				output: strings.TrimLeft(`
+a
++-- i
+:   +-- u
+:       +-- k
++-- kk
+    +-- t
+`, "\n"),
+				err: nil,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			buf := &bytes.Buffer{}
+			callback := func(wn *gtree.WalkerNode) error {
+				fmt.Fprintln(buf, wn.Row())
+				return nil
+			}
+			gotErr := gtree.Walk(tt.in.input, callback, tt.in.options...)
+			if gotErr != nil || tt.out.err != nil {
+				if gotErr.Error() != tt.out.err.Error() {
+					t.Errorf("\ngotErr: \n%s\nwantErr: \n%s", gotErr, tt.out.err)
+				}
+			}
+			got := buf.String()
+			if got != tt.out.output {
+				t.Errorf("\ngot: \n%s\nwant: \n%s", got, tt.out.output)
+			}
+		})
+	}
+}