Improve unit test coverage for utility packages

closer_test.go

@@ -0,0 +1,56 @@
+// CGo binding for Avahi
+//
+// Copyright (C) 2024 and up by Alexander Pevzner (pzz@apevzner.com)
+// See LICENSE for license terms and conditions
+//
+// Closers tests
+//
+//go:build linux || freebsd
+
+package avahi
+
+import "testing"
+
+type mockCloser struct {
+	closed bool
+}
+
+func (m *mockCloser) Close() {
+	m.closed = true
+}
+
+func TestClosers(t *testing.T) {
+	t.Run("Lifecycle", func(t *testing.T) {
+		var set closers
+		set.init()
+
+		c1 := &mockCloser{}
+		c2 := &mockCloser{}
+
+		set.add(c1)
+		set.add(c2)
+
+		if len(set) != 2 {
+			t.Errorf("expected 2 closers, got %d", len(set))
+		}
+
+		set.del(c1)
+		if len(set) != 1 {
+			t.Errorf("expected 1 closer after deletion, got %d", len(set))
+		}
+
+		set.close()
+		if !c2.closed {
+			t.Error("c2 should have been closed")
+		}
+		if c1.closed {
+			t.Error("c1 should not have been closed (it was deleted from the set)")
+		}
+	})
+
+	t.Run("EmptySet", func(t *testing.T) {
+		var set closers
+		set.init()
+		set.close() // Should not panic
+	})
+}

localhost_test.go

@@ -0,0 +1,55 @@
+// CGo binding for Avahi
+//
+// Copyright (C) 2024 and up by Alexander Pevzner (pzz@apevzner.com)
+// See LICENSE for license terms and conditions
+//
+// Localhost handling tests
+//
+//go:build linux || freebsd
+
+package avahi
+
+import "testing"
+
+func TestIsLocalhost(t *testing.T) {
+	tests := []struct {
+		hostname string
+		expected bool
+	}{
+		{
+			hostname: "localhost",
+			expected: true,
+		},
+		{
+			hostname: "localhost.localdomain",
+			expected: true,
+		},
+		{
+			hostname: "LOCALHOST",
+			expected: true,
+		},
+		{
+			hostname: "LocalHost.LocalDomain",
+			expected: true,
+		},
+		{
+			hostname: "example.com",
+			expected: false,
+		},
+		{
+			hostname: "127.0.0.1",
+			expected: false, // isLocalhost only checks string matches
+		},
+		{
+			hostname: "",
+			expected: false,
+		},
+	}
+
+	for _, test := range tests {
+		result := isLocalhost(test.hostname)
+		if result != test.expected {
+			t.Errorf("isLocalhost(%q): expected %v, got %v", test.hostname, test.expected, result)
+		}
+	}
+}