Fix history and add tests

history.go

@@ -14,7 +14,10 @@ func (h *History) Add(input string) {
 }
 
 func (h *History) Clear() {
-	copy(h.tmp, h.histories)
+	h.tmp = make([]string, len(h.histories))
+	for i := range h.histories {
+		h.tmp[i] = h.histories[i]
+	}
 	h.tmp = append(h.tmp, "")
 	h.selected = len(h.tmp) - 1
 }

history_test.go

@@ -0,0 +1,62 @@
+package prompt
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestClear(t *testing.T) {
+	h := NewHistory()
+	h.Add("foo")
+	h.Clear()
+	expected := &History{
+		histories: []string{"foo"},
+		tmp:       []string{"foo", ""},
+		selected:  1,
+	}
+	if !reflect.DeepEqual(expected, h) {
+		t.Errorf("Should be %#v, but got %#v", expected, h)
+	}
+}
+
+func TestAdd(t *testing.T) {
+	h := NewHistory()
+	h.Add("echo 1")
+	expected := &History{
+		histories: []string{"echo 1"},
+		tmp:       []string{"echo 1", ""},
+		selected:  1,
+	}
+	if !reflect.DeepEqual(h, expected) {
+		t.Errorf("Should be %v, but got %v", expected, h)
+	}
+}
+
+func TestOlder(t *testing.T) {
+	h := NewHistory()
+	h.Add("echo 1")
+
+	// Prepare buffer
+	buf := NewBuffer()
+	buf.InsertText("echo 2", false, true)
+
+	// [1 time] Call Older function
+	buf1, changed := h.Older(buf)
+	if !changed {
+		t.Error("Should be changed history but not changed.")
+	}
+	if buf1.Text() != "echo 1" {
+		t.Errorf("Should be %#v, but got %#v", "echo 1", buf1.Text())
+	}
+
+	// [2 times] Call Older function
+	buf = NewBuffer()
+	buf.InsertText("echo 1", false, true)
+	buf2, changed := h.Older(buf)
+	if changed {
+		t.Error("Should be not changed history but changed.")
+	}
+	if !reflect.DeepEqual("echo 1", buf2.Text()) {
+		t.Errorf("Should be %#v, but got %#v", "echo 1", buf2.Text())
+	}
+}