Do not increment game tick on pause

Author: morozov

pkg/game/game.go

@@ -34,7 +34,9 @@ func NewGame() *Game {
 
 // Update updates a game by one tick.
 func (g *Game) Update() error {
-	g.state.Tick++
+	if !g.state.Paused {
+		g.state.Tick++
+	}
 
 	switch g.state.Screen {
 	case domain.ScreenControlSelection:

pkg/game/game_test.go

@@ -0,0 +1,41 @@
+package game
+
+import (
+	"testing"
+
+	"github.com/morozov/river-raid-ebiten/pkg/domain"
+)
+
+// TestTickFrozenWhenPaused verifies that GameState.Tick does not advance while
+// the game is paused, matching the original where the main loop is blocked by the
+// interrupt handler during pause and state_tick never increments.
+func TestTickFrozenWhenPaused(t *testing.T) {
+	g := NewGame()
+	g.state.Screen = domain.ScreenGameplay
+	g.state.Paused = true
+	before := g.state.Tick
+
+	if err := g.Update(); err != nil {
+		t.Fatalf("Update returned error: %v", err)
+	}
+
+	if g.state.Tick != before {
+		t.Errorf("Tick advanced during pause: got %d, want %d", g.state.Tick, before)
+	}
+}
+
+// TestTickAdvancesWhenNotPaused verifies that GameState.Tick increments by one
+// per Update call during normal (non-paused) operation.
+func TestTickAdvancesWhenNotPaused(t *testing.T) {
+	g := NewGame()
+	g.state.Screen = domain.ScreenControlSelection
+	before := g.state.Tick
+
+	if err := g.Update(); err != nil {
+		t.Fatalf("Update returned error: %v", err)
+	}
+
+	if g.state.Tick != before+1 {
+		t.Errorf("Tick = %d, want %d", g.state.Tick, before+1)
+	}
+}