test(17-01): add unit tests for Bot creation and auth filtering

- TestNew_EmptyToken: verify empty token returns error from telego
- TestIsAllowed_EmptyList: verify open access when no restrictions set
- TestIsAllowed_RestrictedList: verify allowlist filtering
- TestCheckRateLimit: verify cooldown enforcement and per-user isolation

pkg/bot/bot_test.go

@@ -0,0 +1,56 @@
+package bot
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNew_EmptyToken(t *testing.T) {
+	_, err := New(Config{Token: ""})
+	require.Error(t, err, "New with empty token should return an error")
+}
+
+func TestIsAllowed_EmptyList(t *testing.T) {
+	b := &Bot{
+		cfg: Config{AllowedChats: nil},
+	}
+	assert.True(t, b.isAllowed(12345), "empty AllowedChats should allow any chat ID")
+	assert.True(t, b.isAllowed(0), "empty AllowedChats should allow zero chat ID")
+	assert.True(t, b.isAllowed(-999), "empty AllowedChats should allow negative chat ID")
+}
+
+func TestIsAllowed_RestrictedList(t *testing.T) {
+	b := &Bot{
+		cfg: Config{AllowedChats: []int64{100, 200}},
+	}
+	assert.True(t, b.isAllowed(100), "chat 100 should be allowed")
+	assert.True(t, b.isAllowed(200), "chat 200 should be allowed")
+	assert.False(t, b.isAllowed(999), "chat 999 should not be allowed")
+	assert.False(t, b.isAllowed(0), "chat 0 should not be allowed")
+}
+
+func TestCheckRateLimit(t *testing.T) {
+	b := &Bot{
+		rateLimits: make(map[int64]time.Time),
+	}
+
+	cooldown := 60 * time.Second
+
+	// First call should be allowed.
+	assert.True(t, b.checkRateLimit(1, cooldown), "first call should pass rate limit")
+
+	// Immediate second call should be blocked.
+	assert.False(t, b.checkRateLimit(1, cooldown), "immediate second call should be rate limited")
+
+	// Different user should not be affected.
+	assert.True(t, b.checkRateLimit(2, cooldown), "different user should pass rate limit")
+
+	// After cooldown expires, the same user should be allowed again.
+	b.rateMu.Lock()
+	b.rateLimits[1] = time.Now().Add(-61 * time.Second)
+	b.rateMu.Unlock()
+	assert.True(t, b.checkRateLimit(1, cooldown), "should pass after cooldown expires")
+}