test(channelserver): add unit tests for helpers, kouryou, scenario, seibattle, and distitem handlers

Cover previously untested handler files with mock-based unit tests:
- handlers_helpers: load/save character data, ack helpers, updateRights
- handlers_kouryou: get/add/exchange points with success and error paths
- handlers_scenario: scenario counter serialization, 128-entry trim, category exchange flags
- handlers_seibattle: all type codes, Earth response format, data size validation
- handlers_distitem: enumerate/apply/acquire distributions, description retrieval

server/channelserver/handlers_scenario_test.go

@@ -0,0 +1,177 @@
+package channelserver
+
+import (
+	"encoding/binary"
+	"errors"
+	"testing"
+
+	"erupe-ce/network/mhfpacket"
+)
+
+// --- mockScenarioRepo ---
+
+type mockScenarioRepo struct {
+	scenarios []Scenario
+	err       error
+}
+
+func (m *mockScenarioRepo) GetCounters() ([]Scenario, error) {
+	return m.scenarios, m.err
+}
+
+func TestHandleMsgMhfInfoScenarioCounter_Empty(t *testing.T) {
+	server := createMockServer()
+	server.scenarioRepo = &mockScenarioRepo{}
+	session := createMockSession(1, server)
+
+	pkt := &mhfpacket.MsgMhfInfoScenarioCounter{AckHandle: 100}
+	handleMsgMhfInfoScenarioCounter(session, pkt)
+
+	select {
+	case p := <-session.sendPackets:
+		_, errCode, ackData := parseAckBufData(t, p.data)
+		if errCode != 0 {
+			t.Errorf("ErrorCode = %d, want 0", errCode)
+		}
+		if len(ackData) < 1 {
+			t.Fatal("AckData too short")
+		}
+		if ackData[0] != 0 {
+			t.Errorf("scenario count = %d, want 0", ackData[0])
+		}
+	default:
+		t.Fatal("No response queued")
+	}
+}
+
+func TestHandleMsgMhfInfoScenarioCounter_WithScenarios(t *testing.T) {
+	server := createMockServer()
+	server.scenarioRepo = &mockScenarioRepo{
+		scenarios: []Scenario{
+			{MainID: 1000, CategoryID: 0},
+			{MainID: 2000, CategoryID: 3},
+			{MainID: 3000, CategoryID: 6},
+			{MainID: 4000, CategoryID: 7},
+			{MainID: 5000, CategoryID: 1},
+		},
+	}
+	session := createMockSession(1, server)
+
+	pkt := &mhfpacket.MsgMhfInfoScenarioCounter{AckHandle: 100}
+	handleMsgMhfInfoScenarioCounter(session, pkt)
+
+	select {
+	case p := <-session.sendPackets:
+		_, _, data := parseAckBufData(t, p.data)
+		if len(data) < 1 {
+			t.Fatal("AckData too short")
+		}
+		count := data[0]
+		if count != 5 {
+			t.Errorf("scenario count = %d, want 5", count)
+		}
+
+		// Each scenario: mainID(4) + exchange(1) + categoryID(1) = 6 bytes
+		expectedLen := 1 + 5*6
+		if len(data) != expectedLen {
+			t.Errorf("AckData len = %d, want %d", len(data), expectedLen)
+		}
+
+		// Verify first scenario (categoryID=0, exchange=false)
+		mainID := binary.BigEndian.Uint32(data[1:5])
+		if mainID != 1000 {
+			t.Errorf("first mainID = %d, want 1000", mainID)
+		}
+		if data[5] != 0 {
+			t.Errorf("categoryID=0 should have exchange=false, got %d", data[5])
+		}
+
+		// Verify second scenario (categoryID=3, exchange=true)
+		if data[5+6] != 1 {
+			t.Errorf("categoryID=3 should have exchange=true, got %d", data[5+6])
+		}
+	default:
+		t.Fatal("No response queued")
+	}
+}
+
+func TestHandleMsgMhfInfoScenarioCounter_TrimTo128(t *testing.T) {
+	server := createMockServer()
+	scenarios := make([]Scenario, 200)
+	for i := range scenarios {
+		scenarios[i] = Scenario{MainID: uint32(i), CategoryID: 0}
+	}
+	server.scenarioRepo = &mockScenarioRepo{scenarios: scenarios}
+	session := createMockSession(1, server)
+
+	pkt := &mhfpacket.MsgMhfInfoScenarioCounter{AckHandle: 100}
+	handleMsgMhfInfoScenarioCounter(session, pkt)
+
+	select {
+	case p := <-session.sendPackets:
+		_, _, data := parseAckBufData(t, p.data)
+		if data[0] != 128 {
+			t.Errorf("scenario count = %d, want 128 (trimmed)", data[0])
+		}
+	default:
+		t.Fatal("No response queued")
+	}
+}
+
+func TestHandleMsgMhfInfoScenarioCounter_DBError(t *testing.T) {
+	server := createMockServer()
+	server.scenarioRepo = &mockScenarioRepo{err: errors.New("db error")}
+	session := createMockSession(1, server)
+
+	pkt := &mhfpacket.MsgMhfInfoScenarioCounter{AckHandle: 100}
+	handleMsgMhfInfoScenarioCounter(session, pkt)
+
+	select {
+	case p := <-session.sendPackets:
+		if len(p.data) == 0 {
+			t.Fatal("Should still respond on error")
+		}
+	default:
+		t.Fatal("No response queued")
+	}
+}
+
+func TestHandleMsgMhfInfoScenarioCounter_CategoryExchangeFlags(t *testing.T) {
+	tests := []struct {
+		name       string
+		categoryID uint8
+		wantExch   bool
+	}{
+		{"Basic", 0, false},
+		{"Veteran", 1, false},
+		{"Other (exchange)", 3, true},
+		{"Pallone (exchange)", 6, true},
+		{"Diva (exchange)", 7, true},
+		{"Unknown category 2", 2, false},
+		{"Unknown category 4", 4, false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			server := createMockServer()
+			server.scenarioRepo = &mockScenarioRepo{
+				scenarios: []Scenario{{MainID: 1, CategoryID: tt.categoryID}},
+			}
+			session := createMockSession(1, server)
+
+			pkt := &mhfpacket.MsgMhfInfoScenarioCounter{AckHandle: 100}
+			handleMsgMhfInfoScenarioCounter(session, pkt)
+
+			select {
+			case p := <-session.sendPackets:
+				_, _, data := parseAckBufData(t, p.data)
+				isExchange := data[5] != 0
+				if isExchange != tt.wantExch {
+					t.Errorf("exchange = %v, want %v for categoryID=%d", isExchange, tt.wantExch, tt.categoryID)
+				}
+			default:
+				t.Fatal("No response queued")
+			}
+		})
+	}
+}