feat: implement item management handlers with corresponding tests

internal/handlers/addItemHandler_test.go

@@ -0,0 +1,87 @@
+package handlers_test
+
+import (
+	"testing"
+
+	"github.com/StevanFreeborn/term-tier/internal/handlers"
+	"github.com/StevanFreeborn/term-tier/internal/state"
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+func TestNewAddItemHandler(t *testing.T) {
+	h := handlers.NewAddItemHandler()
+
+	if h.Description() != "Add new item" {
+		t.Errorf("Expected description 'Add new item', got %q", h.Description())
+	}
+
+	keys := h.KeysHandled()
+
+	if len(keys) != 1 || keys[0] != "n" {
+		t.Errorf("Expected keys ['n'], got %v", keys)
+	}
+}
+
+func TestAddItemHandler_Match(t *testing.T) {
+	h := handlers.NewAddItemHandler()
+
+	tests := []struct {
+		name     string
+		mode     state.Mode
+		key      string
+		expected bool
+	}{
+		{
+			name:     "Matches 'n' in Navigation Mode",
+			mode:     state.NavigationMode,
+			key:      "n",
+			expected: true,
+		},
+		{
+			name:     "Ignores 'n' in Input Mode",
+			mode:     state.InputMode,
+			key:      "n",
+			expected: false,
+		},
+		{
+			name:     "Ignores 'q' in Navigation Mode",
+			mode:     state.NavigationMode,
+			key:      "q",
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := state.New(state.WithMode(tt.mode))
+			msg := tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune(tt.key)}
+
+			if got := h.Match(s, msg); got != tt.expected {
+				t.Errorf("Match() = %v, want %v", got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestAddItemHandler_Handle(t *testing.T) {
+	h := handlers.NewAddItemHandler()
+
+	s := state.New(state.WithMode(state.NavigationMode))
+
+	msg := tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune("n")}
+	cmd := h.Handle(s, msg)
+
+	if s.Mode() != state.InputMode {
+		t.Errorf("Expected state to switch to InputMode, got %v", s.Mode())
+	}
+
+	expectedTitle := "Add new item"
+
+	if s.InputTitle() != expectedTitle {
+		t.Errorf("Expected input title %q, got %q", expectedTitle, s.InputTitle())
+	}
+
+	if cmd == nil {
+		t.Error("Expected Handle to return a tea.Cmd (cursor blink), got nil")
+	}
+}