rs2322tcp/internal/client/virtual_port_manager_test.go

/*
 * ============================================================================
 * Projekt.....: rs2322tcp
 * Datei.......: internal/client/virtual_port_manager_test.go
 * Copyright (C) 2026 Dieter Lang
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 * Beschreibung:
 * Tests für die Auswahl und Verwaltung virtueller serieller Ports.
 * ============================================================================
 */
package client

import (
	"testing"

	"git.lang-dieter.de/rs2322tcp/internal/config"
)

///////////////////////////////////////////////////////////////////////////////
// Tests
///////////////////////////////////////////////////////////////////////////////

func TestNewVirtualPortManager(t *testing.T) {
	cfg := config.VirtualPortRangeConfig{
		First: 100,
		Last:  199,
	}

	manager := NewVirtualPortManager(cfg)

	if manager == nil {
		t.Fatal("NewVirtualPortManager() returned nil")
	}

	if manager.first != 100 {
		t.Errorf("first = %d, want 100", manager.first)
	}

	if manager.last != 199 {
		t.Errorf("last = %d, want 199", manager.last)
	}
}

func TestVirtualPortManagerReserveFirst(t *testing.T) {
	manager := NewVirtualPortManager(config.VirtualPortRangeConfig{
		First: 100,
		Last:  199,
	})

	number, err := manager.Reserve()
	if err != nil {
		t.Fatalf("Reserve() failed: %v", err)
	}

	if number != 100 {
		t.Errorf("Reserve() = %d, want 100", number)
	}
}

func TestVirtualPortManagerReserveNextFree(t *testing.T) {
	manager := NewVirtualPortManager(config.VirtualPortRangeConfig{
		First: 100,
		Last:  199,
	})

	first, err := manager.Reserve()
	if err != nil {
		t.Fatalf("first Reserve() failed: %v", err)
	}

	second, err := manager.Reserve()
	if err != nil {
		t.Fatalf("second Reserve() failed: %v", err)
	}

	if first != 100 {
		t.Errorf("first Reserve() = %d, want 100", first)
	}

	if second != 101 {
		t.Errorf("second Reserve() = %d, want 101", second)
	}
}

func TestVirtualPortManagerRelease(t *testing.T) {
	manager := NewVirtualPortManager(config.VirtualPortRangeConfig{
		First: 100,
		Last:  199,
	})

	number, err := manager.Reserve()
	if err != nil {
		t.Fatalf("Reserve() failed: %v", err)
	}

	manager.Release(number)

	reused, err := manager.Reserve()
	if err != nil {
		t.Fatalf("Reserve() after Release() failed: %v", err)
	}

	if reused != 100 {
		t.Errorf("Reserve() after Release() = %d, want 100",
			reused)
	}
}

func TestVirtualPortManagerSkipsReservedPorts(t *testing.T) {
	manager := NewVirtualPortManager(config.VirtualPortRangeConfig{
		First: 100,
		Last:  199,
	})

	for i := 0; i < 3; i++ {
		if _, err := manager.Reserve(); err != nil {
			t.Fatalf("Reserve() %d failed: %v", i+1, err)
		}
	}

	number, err := manager.Reserve()
	if err != nil {
		t.Fatalf("fourth Reserve() failed: %v", err)
	}

	if number != 103 {
		t.Errorf("fourth Reserve() = %d, want 103", number)
	}
}

func TestVirtualPortManagerCustomRange(t *testing.T) {
	manager := NewVirtualPortManager(config.VirtualPortRangeConfig{
		First: 200,
		Last:  299,
	})

	number, err := manager.Reserve()
	if err != nil {
		t.Fatalf("Reserve() failed: %v", err)
	}

	if number != 200 {
		t.Errorf("Reserve() = %d, want 200", number)
	}
}

func TestVirtualPortManagerNoFreePort(t *testing.T) {
	manager := NewVirtualPortManager(config.VirtualPortRangeConfig{
		First: 100,
		Last:  102,
	})

	for i := 0; i < 3; i++ {
		if _, err := manager.Reserve(); err != nil {
			t.Fatalf("Reserve() %d failed: %v", i+1, err)
		}
	}

	if _, err := manager.Reserve(); err == nil {
		t.Fatal("Reserve() succeeded, want no-free-port error")
	}
}

func TestVirtualPortManagerPortPath(t *testing.T) {
	manager := NewVirtualPortManager(config.VirtualPortRangeConfig{
		First: 100,
		Last:  199,
	})

	tests := []struct {
		number int
		want   string
	}{
		{
			number: 100,
			want:   "/dev/ttyUSB100",
		},
		{
			number: 123,
			want:   "/dev/ttyUSB123",
		},
		{
			number: 199,
			want:   "/dev/ttyUSB199",
		},
	}

	for _, test := range tests {
		got := manager.PortPath(test.number)

		if got != test.want {
			t.Errorf(
				"PortPath(%d) = %q, want %q",
				test.number,
				got,
				test.want,
			)
		}
	}
}

func TestVirtualPortManagerNil(t *testing.T) {
	var manager *VirtualPortManager

	if path := manager.PortPath(100); path != "" {
		t.Errorf("nil PortPath() = %q, want empty string", path)
	}

	if _, err := manager.Reserve(); err == nil {
		t.Fatal("nil Reserve() succeeded, want error")
	}

	manager.Release(100)
}