internal/constants/expense.go

@@ -0,0 +1,28 @@
+package constants
+
+type ExpenseStatus string
+
+const (
+	ExpenseStatusDraft    ExpenseStatus = "draft"
+	ExpenseStatusSent     ExpenseStatus = "sent"
+	ExpenseStatusApproved ExpenseStatus = "approved"
+	ExpenseStatusCancel   ExpenseStatus = "cancel"
+)
+
+func GetAllExpenseStatuses() []ExpenseStatus {
+	return []ExpenseStatus{
+		ExpenseStatusDraft,
+		ExpenseStatusSent,
+		ExpenseStatusApproved,
+		ExpenseStatusCancel,
+	}
+}
+
+func IsValidExpenseStatus(status ExpenseStatus) bool {
+	for _, validStatus := range GetAllExpenseStatuses() {
+		if status == validStatus {
+			return true
+		}
+	}
+	return false
+}

internal/contract/analytics_contract.go

@@ -239,13 +239,15 @@ type DashboardOverview struct {
 type ProfitLossAnalyticsRequest struct {
 	OrganizationID uuid.UUID
 	OutletID       *string `form:"outlet_id,omitempty"`
-	Date           string  `form:"date" validate:"required"`
+	DateFrom       string  `form:"date_from" validate:"required"`
+	DateTo         string  `form:"date_to" validate:"required"`
 }
 
 type ProfitLossAnalyticsResponse struct {
 	OrganizationID           uuid.UUID                `json:"organization_id"`
 	OutletID                 *uuid.UUID               `json:"outlet_id,omitempty"`
-	Date                     time.Time                `json:"date"`
+	DateFrom                 time.Time                `json:"date_from"`
+	DateTo                   time.Time                `json:"date_to"`
 	MainSummary              []ProfitLossSummaryRow   `json:"main_summary"`
 	OperationalExpenses      []OperationalExpenseItem `json:"operational_expenses"`
 	OperationalExpensesTotal float64                  `json:"operational_expenses_total"`

internal/contract/purchase_order_contract.go

@@ -10,7 +10,7 @@ type CreatePurchaseOrderRequest struct {
 	VendorID          uuid.UUID                        `json:"vendor_id" validate:"required"`
 	PONumber          string                           `json:"po_number" validate:"required,min=1,max=50"`
 	TransactionDate   string                           `json:"transaction_date" validate:"required"`    // Format: YYYY-MM-DD
-	DueDate           string                           `json:"due_date" validate:"required"`          // Format: YYYY-MM-DD
+	DueDate           *string                          `json:"due_date,omitempty" validate:"omitempty"` // Format: YYYY-MM-DD
 	Reference         *string                          `json:"reference,omitempty" validate:"omitempty,max=100"`
 	Status            *string                          `json:"status,omitempty" validate:"omitempty,oneof=draft sent approved received cancelled"`
 	Message           *string                          `json:"message,omitempty" validate:"omitempty"`
@@ -53,7 +53,7 @@ type PurchaseOrderResponse struct {
 	VendorID        uuid.UUID                         `json:"vendor_id"`
 	PONumber        string                            `json:"po_number"`
 	TransactionDate time.Time                         `json:"transaction_date"`
-	DueDate         time.Time                         `json:"due_date"`
+	DueDate         *time.Time                        `json:"due_date"`
 	Reference       *string                           `json:"reference"`
 	Status          string                            `json:"status"`
 	Message         *string                           `json:"message"`

internal/entities/purchase_order.go

@@ -14,7 +14,7 @@ type PurchaseOrder struct {
 	VendorID        uuid.UUID  `gorm:"type:uuid;not null" json:"vendor_id" validate:"required"`
 	PONumber        string     `gorm:"not null;size:50" json:"po_number" validate:"required,min=1,max=50"`
 	TransactionDate time.Time  `gorm:"type:date;not null" json:"transaction_date" validate:"required"`
-	DueDate         time.Time `gorm:"type:date;not null" json:"due_date" validate:"required"`
+	DueDate         *time.Time `gorm:"type:date" json:"due_date" validate:"omitempty"`
 	Reference       *string    `gorm:"size:100" json:"reference" validate:"omitempty,max=100"`
 	Status          string     `gorm:"not null;size:20;default:'draft'" json:"status" validate:"required,oneof=draft sent approved received cancelled"`
 	Message         *string    `gorm:"type:text" json:"message" validate:"omitempty"`

internal/models/analytics.go

@@ -249,13 +249,15 @@ type DashboardOverview struct {
 type ProfitLossAnalyticsRequest struct {
 	OrganizationID uuid.UUID  `validate:"required"`
 	OutletID       *uuid.UUID `validate:"omitempty"`
-	Date           time.Time  `validate:"required"`
+	DateFrom       time.Time  `validate:"required"`
+	DateTo         time.Time  `validate:"required"`
 }
 
 type ProfitLossAnalyticsResponse struct {
 	OrganizationID           uuid.UUID                `json:"organization_id"`
 	OutletID                 *uuid.UUID               `json:"outlet_id,omitempty"`
-	Date                     time.Time                `json:"date"`
+	DateFrom                 time.Time                `json:"date_from"`
+	DateTo                   time.Time                `json:"date_to"`
 	MainSummary              []ProfitLossSummaryRow   `json:"main_summary"`
 	OperationalExpenses      []OperationalExpenseItem `json:"operational_expenses"`
 	OperationalExpensesTotal float64                  `json:"operational_expenses_total"`

internal/models/purchase_order.go

@@ -12,7 +12,7 @@ type PurchaseOrder struct {
 	VendorID        uuid.UUID  `json:"vendor_id"`
 	PONumber        string     `json:"po_number"`
 	TransactionDate time.Time  `json:"transaction_date"`
-	DueDate         time.Time `json:"due_date"`
+	DueDate         *time.Time `json:"due_date"`
 	Reference       *string    `json:"reference"`
 	Status          string     `json:"status"`
 	Message         *string    `json:"message"`
@@ -46,7 +46,7 @@ type PurchaseOrderResponse struct {
 	VendorID        uuid.UUID                         `json:"vendor_id"`
 	PONumber        string                            `json:"po_number"`
 	TransactionDate time.Time                         `json:"transaction_date"`
-	DueDate         time.Time                         `json:"due_date"`
+	DueDate         *time.Time                        `json:"due_date"`
 	Reference       *string                           `json:"reference"`
 	Status          string                            `json:"status"`
 	Message         *string                           `json:"message"`
@@ -84,7 +84,7 @@ type CreatePurchaseOrderRequest struct {
 	VendorID          uuid.UUID                        `json:"vendor_id"`
 	PONumber          string                           `json:"po_number"`
 	TransactionDate   time.Time                        `json:"transaction_date"`
-	DueDate           time.Time                        `json:"due_date"`
+	DueDate           *time.Time                       `json:"due_date,omitempty"`
 	Reference         *string                          `json:"reference,omitempty"`
 	Status            *string                          `json:"status,omitempty"`
 	Message           *string                          `json:"message,omitempty"`

internal/processor/analytics_processor.go

@@ -398,11 +398,19 @@ func (p *AnalyticsProcessorImpl) GetDashboardAnalytics(ctx context.Context, req
 }
 
 func (p *AnalyticsProcessorImpl) GetProfitLossAnalytics(ctx context.Context, req *models.ProfitLossAnalyticsRequest) (*models.ProfitLossAnalyticsResponse, error) {
-	if req.Date.IsZero() {
-		return nil, fmt.Errorf("date is required")
+	if req.DateFrom.IsZero() {
+		return nil, fmt.Errorf("date_from is required")
 	}
 
-	result, err := p.analyticsRepo.GetProfitLossAnalytics(ctx, req.OrganizationID, req.OutletID, req.Date)
+	if req.DateTo.IsZero() {
+		return nil, fmt.Errorf("date_to is required")
+	}
+
+	if req.DateFrom.After(req.DateTo) {
+		return nil, fmt.Errorf("date_from cannot be after date_to")
+	}
+
+	result, err := p.analyticsRepo.GetProfitLossAnalytics(ctx, req.OrganizationID, req.OutletID, req.DateFrom, req.DateTo)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get profit/loss analytics: %w", err)
 	}
@@ -507,7 +515,8 @@ func (p *AnalyticsProcessorImpl) GetProfitLossAnalytics(ctx context.Context, req
 	return &models.ProfitLossAnalyticsResponse{
 		OrganizationID:           req.OrganizationID,
 		OutletID:                 req.OutletID,
-		Date:                     req.Date,
+		DateFrom:                 req.DateFrom,
+		DateTo:                   req.DateTo,
 		MainSummary:              mainSummary,
 		OperationalExpenses:      opsItems,
 		OperationalExpensesTotal: opsTotal,

internal/processor/analytics_processor_test.go

@@ -40,7 +40,7 @@ func (analyticsRepositoryStub) GetDashboardOverview(context.Context, uuid.UUID,
 	return nil, nil
 }
 
-func (analyticsRepositoryStub) GetProfitLossAnalytics(context.Context, uuid.UUID, *uuid.UUID, time.Time) (*entities.ProfitLossAnalytics, error) {
+func (analyticsRepositoryStub) GetProfitLossAnalytics(context.Context, uuid.UUID, *uuid.UUID, time.Time, time.Time) (*entities.ProfitLossAnalytics, error) {
 	return nil, nil
 }
 

internal/processor/expense_processor_test.go

@@ -0,0 +1,136 @@
+package processor
+
+import (
+	"context"
+	"testing"
+
+	"apskel-pos-be/internal/entities"
+	"apskel-pos-be/internal/models"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+)
+
+type expenseRepositoryCaptureStub struct {
+	createdExpense *entities.Expense
+	createdItems   []*entities.ExpenseItem
+}
+
+func (s *expenseRepositoryCaptureStub) Create(_ context.Context, expense *entities.Expense) error {
+	if expense.ID == uuid.Nil {
+		expense.ID = uuid.New()
+	}
+	s.createdExpense = expense
+	return nil
+}
+
+func (s *expenseRepositoryCaptureStub) GetByID(context.Context, uuid.UUID) (*entities.Expense, error) {
+	if s.createdExpense == nil {
+		return nil, nil
+	}
+	items := make([]entities.ExpenseItem, len(s.createdItems))
+	for i, item := range s.createdItems {
+		items[i] = *item
+	}
+	s.createdExpense.Items = items
+	return s.createdExpense, nil
+}
+
+func (*expenseRepositoryCaptureStub) GetByIDAndOrganizationID(context.Context, uuid.UUID, uuid.UUID) (*entities.Expense, error) {
+	return nil, nil
+}
+func (*expenseRepositoryCaptureStub) Update(context.Context, *entities.Expense) error { return nil }
+func (*expenseRepositoryCaptureStub) Delete(context.Context, uuid.UUID) error         { return nil }
+func (*expenseRepositoryCaptureStub) List(context.Context, uuid.UUID, map[string]interface{}, int, int) ([]*entities.Expense, int64, error) {
+	return nil, 0, nil
+}
+func (s *expenseRepositoryCaptureStub) CreateItem(_ context.Context, item *entities.ExpenseItem) error {
+	if item.ID == uuid.Nil {
+		item.ID = uuid.New()
+	}
+	s.createdItems = append(s.createdItems, item)
+	return nil
+}
+func (*expenseRepositoryCaptureStub) DeleteItemsByExpenseID(context.Context, uuid.UUID) error {
+	return nil
+}
+
+func TestExpenseProcessorCreatePersistsItemName(t *testing.T) {
+	repo := &expenseRepositoryCaptureStub{}
+	p := NewExpenseProcessorImpl(repo)
+	chartOfAccountID := uuid.New()
+
+	resp, err := p.CreateExpense(context.Background(), uuid.New(), &models.CreateExpenseRequest{
+		Receiver:        "Cashier",
+		TransactionDate: "2026-05-29",
+		CodeNumber:      "EXP-001",
+		OutletID:        uuid.NewString(),
+		Total:           10000,
+		Items: []models.CreateExpenseItemRequest{
+			{
+				ChartOfAccountID: chartOfAccountID.String(),
+				Item:             "Cleaning supplies",
+				Amount:           10000,
+			},
+		},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, resp)
+	require.Len(t, repo.createdItems, 1)
+	require.Equal(t, "Cleaning supplies", repo.createdItems[0].Item)
+	require.Len(t, resp.Items, 1)
+	require.Equal(t, "Cleaning supplies", resp.Items[0].Item)
+}
+
+func TestExpenseProcessorCreateDefaultsStatusToDraft(t *testing.T) {
+	repo := &expenseRepositoryCaptureStub{}
+	p := NewExpenseProcessorImpl(repo)
+
+	resp, err := p.CreateExpense(context.Background(), uuid.New(), &models.CreateExpenseRequest{
+		Receiver:        "Cashier",
+		TransactionDate: "2026-05-29",
+		CodeNumber:      "EXP-001",
+		OutletID:        uuid.NewString(),
+		Total:           10000,
+		Items: []models.CreateExpenseItemRequest{
+			{
+				ChartOfAccountID: uuid.NewString(),
+				Item:             "Cleaning supplies",
+				Amount:           10000,
+			},
+		},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, resp)
+	require.Equal(t, "draft", repo.createdExpense.Status)
+	require.Equal(t, "draft", resp.Status)
+}
+
+func TestExpenseProcessorCreatePersistsProvidedStatus(t *testing.T) {
+	repo := &expenseRepositoryCaptureStub{}
+	p := NewExpenseProcessorImpl(repo)
+	status := "approved"
+
+	resp, err := p.CreateExpense(context.Background(), uuid.New(), &models.CreateExpenseRequest{
+		Receiver:        "Cashier",
+		TransactionDate: "2026-05-29",
+		CodeNumber:      "EXP-001",
+		OutletID:        uuid.NewString(),
+		Status:          &status,
+		Total:           10000,
+		Items: []models.CreateExpenseItemRequest{
+			{
+				ChartOfAccountID: uuid.NewString(),
+				Item:             "Cleaning supplies",
+				Amount:           10000,
+			},
+		},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, resp)
+	require.Equal(t, "approved", repo.createdExpense.Status)
+	require.Equal(t, "approved", resp.Status)
+}

internal/processor/purchase_order_processor.go

@@ -175,7 +175,7 @@ func (p *PurchaseOrderProcessorImpl) UpdatePurchaseOrder(ctx context.Context, id
 		poEntity.TransactionDate = *req.TransactionDate
 	}
 	if req.DueDate != nil {
-		poEntity.DueDate = *req.DueDate
+		poEntity.DueDate = req.DueDate
 	}
 	if req.Reference != nil {
 		poEntity.Reference = req.Reference

internal/repository/analytics_repository.go

@@ -17,7 +17,7 @@ type AnalyticsRepository interface {
 	GetProductAnalytics(ctx context.Context, organizationID uuid.UUID, outletID *uuid.UUID, dateFrom, dateTo time.Time, limit int) ([]*entities.ProductAnalytics, error)
 	GetProductAnalyticsPerCategory(ctx context.Context, organizationID uuid.UUID, outletID *uuid.UUID, dateFrom, dateTo time.Time) ([]*entities.ProductAnalyticsPerCategory, error)
 	GetDashboardOverview(ctx context.Context, organizationID uuid.UUID, outletID *uuid.UUID, dateFrom, dateTo time.Time) (*entities.DashboardOverview, error)
-	GetProfitLossAnalytics(ctx context.Context, organizationID uuid.UUID, outletID *uuid.UUID, date time.Time) (*entities.ProfitLossAnalytics, error)
+	GetProfitLossAnalytics(ctx context.Context, organizationID uuid.UUID, outletID *uuid.UUID, dateFrom, dateTo time.Time) (*entities.ProfitLossAnalytics, error)
 }
 
 type AnalyticsRepositoryImpl struct {
@@ -432,9 +432,9 @@ func (r *AnalyticsRepositoryImpl) GetDashboardOverview(ctx context.Context, orga
 	return &result, nil
 }
 
-func (r *AnalyticsRepositoryImpl) GetProfitLossAnalytics(ctx context.Context, organizationID uuid.UUID, outletID *uuid.UUID, date time.Time) (*entities.ProfitLossAnalytics, error) {
-	mtdStart := time.Date(date.Year(), date.Month(), 1, 0, 0, 0, 0, date.Location())
-	todayStart := time.Date(date.Year(), date.Month(), date.Day(), 0, 0, 0, 0, date.Location())
+func (r *AnalyticsRepositoryImpl) GetProfitLossAnalytics(ctx context.Context, organizationID uuid.UUID, outletID *uuid.UUID, dateFrom, dateTo time.Time) (*entities.ProfitLossAnalytics, error) {
+	mtdStart := time.Date(dateTo.Year(), dateTo.Month(), 1, 0, 0, 0, 0, dateTo.Location())
+	todayStart := time.Date(dateTo.Year(), dateTo.Month(), dateTo.Day(), 0, 0, 0, 0, dateTo.Location())
 	todayEnd := todayStart.Add(24 * time.Hour).Add(-time.Nanosecond)
 
 	type revenueCostResult struct {

internal/service/analytics_service.go

@@ -306,8 +306,16 @@ func (s *AnalyticsServiceImpl) validateProfitLossAnalyticsRequest(req *models.Pr
 		return fmt.Errorf("organization_id is required")
 	}
 
-	if req.Date.IsZero() {
-		return fmt.Errorf("date is required")
+	if req.DateFrom.IsZero() {
+		return fmt.Errorf("date_from is required")
+	}
+
+	if req.DateTo.IsZero() {
+		return fmt.Errorf("date_to is required")
+	}
+
+	if req.DateFrom.After(req.DateTo) {
+		return fmt.Errorf("date_from cannot be after date_to")
 	}
 
 	return nil

internal/service/analytics_service_test.go

@@ -119,3 +119,50 @@ func TestAnalyticsServiceGetPurchasingAnalyticsAllowsEmptyGroupBy(t *testing.T)
 	require.NoError(t, err)
 	require.NotNil(t, resp)
 }
+
+func TestAnalyticsServiceGetProfitLossAnalyticsValidation(t *testing.T) {
+	service := NewAnalyticsServiceImpl(analyticsProcessorStub{})
+	now := time.Date(2026, 5, 1, 0, 0, 0, 0, time.UTC)
+
+	tests := []struct {
+		name    string
+		req     *models.ProfitLossAnalyticsRequest
+		wantErr string
+	}{
+		{
+			name: "missing date_from",
+			req: &models.ProfitLossAnalyticsRequest{
+				OrganizationID: uuid.New(),
+				DateTo:         now,
+			},
+			wantErr: "date_from is required",
+		},
+		{
+			name: "missing date_to",
+			req: &models.ProfitLossAnalyticsRequest{
+				OrganizationID: uuid.New(),
+				DateFrom:       now,
+			},
+			wantErr: "date_to is required",
+		},
+		{
+			name: "reversed dates",
+			req: &models.ProfitLossAnalyticsRequest{
+				OrganizationID: uuid.New(),
+				DateFrom:       now.AddDate(0, 0, 1),
+				DateTo:         now,
+			},
+			wantErr: "date_from cannot be after date_to",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			resp, err := service.GetProfitLossAnalytics(context.Background(), tt.req)
+
+			require.Nil(t, resp)
+			require.Error(t, err)
+			require.Contains(t, err.Error(), tt.wantErr)
+		})
+	}
+}

internal/service/report_service.go

@@ -113,7 +113,7 @@ func (s *ReportServiceImpl) GenerateDailyTransactionPDF(ctx context.Context, org
 	end := day.Add(24*time.Hour - time.Nanosecond)
 
 	salesReq := &models.SalesAnalyticsRequest{OrganizationID: orgID, OutletID: &outID, DateFrom: start, DateTo: end, GroupBy: "day"}
-	plReq := &models.ProfitLossAnalyticsRequest{OrganizationID: orgID, OutletID: &outID, Date: day}
+	plReq := &models.ProfitLossAnalyticsRequest{OrganizationID: orgID, OutletID: &outID, DateFrom: start, DateTo: end}
 	productReq := &models.ProductAnalyticsRequest{OrganizationID: orgID, OutletID: &outID, DateFrom: start, DateTo: end, Limit: 1000}
 
 	sales, err := s.analyticsService.GetSalesAnalytics(ctx, salesReq)

internal/transformer/analytics_transformer.go

@@ -432,19 +432,24 @@ func ProfitLossAnalyticsContractToModel(req *contract.ProfitLossAnalyticsRequest
 		return nil, fmt.Errorf("request cannot be nil")
 	}
 
-	dateTime, err := util.ParseDateToJakartaTime(req.Date)
+	dateFrom, dateTo, err := util.ParseDateRangeToJakartaTime(req.DateFrom, req.DateTo)
 	if err != nil {
-		return nil, fmt.Errorf("invalid date format: %w", err)
+		return nil, fmt.Errorf("invalid date range: %w", err)
 	}
 
-	if dateTime == nil {
-		return nil, fmt.Errorf("date is required")
+	if dateFrom == nil {
+		return nil, fmt.Errorf("date_from is required")
+	}
+
+	if dateTo == nil {
+		return nil, fmt.Errorf("date_to is required")
 	}
 
 	return &models.ProfitLossAnalyticsRequest{
 		OrganizationID: req.OrganizationID,
 		OutletID:       parseOutletID(req.OutletID),
-		Date:           *dateTime,
+		DateFrom:       *dateFrom,
+		DateTo:         *dateTo,
 	}, nil
 }
 
@@ -469,7 +474,8 @@ func ProfitLossAnalyticsModelToContract(resp *models.ProfitLossAnalyticsResponse
 	return &contract.ProfitLossAnalyticsResponse{
 		OrganizationID:           resp.OrganizationID,
 		OutletID:                 resp.OutletID,
-		Date:                     resp.Date,
+		DateFrom:                 resp.DateFrom,
+		DateTo:                   resp.DateTo,
 		MainSummary:              mainSummary,
 		OperationalExpenses:      opsItems,
 		OperationalExpensesTotal: resp.OperationalExpensesTotal,

internal/transformer/analytics_transformer_test.go

@@ -74,3 +74,40 @@ func TestPurchasingAnalyticsModelToContractOmitsNilOutletName(t *testing.T) {
 	require.NoError(t, err)
 	require.NotContains(t, string(payload), "outlet_name")
 }
+
+func TestProfitLossAnalyticsContractToModelParsesDateRange(t *testing.T) {
+	orgID := uuid.New()
+	outletID := uuid.New().String()
+
+	result, err := ProfitLossAnalyticsContractToModel(&contract.ProfitLossAnalyticsRequest{
+		OrganizationID: orgID,
+		OutletID:       &outletID,
+		DateFrom:       "01-05-2026",
+		DateTo:         "29-05-2026",
+	})
+
+	require.NoError(t, err)
+	require.Equal(t, orgID, result.OrganizationID)
+	require.NotNil(t, result.OutletID)
+	require.Equal(t, outletID, result.OutletID.String())
+
+	location, err := time.LoadLocation("Asia/Jakarta")
+	require.NoError(t, err)
+	require.Equal(t, time.Date(2026, 5, 1, 0, 0, 0, 0, location), result.DateFrom)
+	require.Equal(t, time.Date(2026, 5, 29, 23, 59, 59, int(time.Second-time.Nanosecond), location), result.DateTo)
+}
+
+func TestProfitLossAnalyticsModelToContractCopiesDateRange(t *testing.T) {
+	dateFrom := time.Date(2026, 5, 1, 0, 0, 0, 0, time.UTC)
+	dateTo := time.Date(2026, 5, 29, 23, 59, 59, int(time.Second-time.Nanosecond), time.UTC)
+
+	result := ProfitLossAnalyticsModelToContract(&models.ProfitLossAnalyticsResponse{
+		OrganizationID: uuid.New(),
+		DateFrom:       dateFrom,
+		DateTo:         dateTo,
+	})
+
+	require.NotNil(t, result)
+	require.Equal(t, dateFrom, result.DateFrom)
+	require.Equal(t, dateTo, result.DateTo)
+}

internal/transformer/purchase_order_transformer.go

@@ -25,11 +25,15 @@ func CreatePurchaseOrderRequestToModel(req *contract.CreatePurchaseOrderRequest)
 		return nil, err
 	}
 
-	// Parse due date
-	dueDate, err := time.Parse("2006-01-02", req.DueDate)
+	// Parse due date if provided
+	var dueDate *time.Time
+	if req.DueDate != nil && *req.DueDate != "" {
+		parsedDate, err := time.Parse("2006-01-02", *req.DueDate)
 		if err != nil {
 			return nil, err
 		}
+		dueDate = &parsedDate
+	}
 
 	return &models.CreatePurchaseOrderRequest{
 		VendorID:          req.VendorID,

internal/transformer/purchase_order_transformer_test.go

@@ -0,0 +1,43 @@
+package transformer
+
+import (
+	"encoding/json"
+	"testing"
+
+	"apskel-pos-be/internal/contract"
+	"apskel-pos-be/internal/models"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCreatePurchaseOrderRequestToModelAllowsMissingDueDate(t *testing.T) {
+	result, err := CreatePurchaseOrderRequestToModel(&contract.CreatePurchaseOrderRequest{
+		VendorID:        uuid.New(),
+		PONumber:        "PO-001",
+		TransactionDate: "2026-05-29",
+		Items: []contract.CreatePurchaseOrderItemRequest{
+			{
+				IngredientID: uuid.New(),
+				Quantity:     1,
+				UnitID:       uuid.New(),
+				Amount:       1000,
+			},
+		},
+	})
+
+	require.NoError(t, err)
+	require.Nil(t, result.DueDate)
+}
+
+func TestPurchaseOrderModelResponseToResponseIncludesNullDueDate(t *testing.T) {
+	result := PurchaseOrderModelResponseToResponse(&models.PurchaseOrderResponse{
+		ID:       uuid.New(),
+		VendorID: uuid.New(),
+		PONumber: "PO-001",
+	})
+
+	payload, err := json.Marshal(result)
+	require.NoError(t, err)
+	require.Contains(t, string(payload), `"due_date":null`)
+}

internal/validator/expense_validator_test.go

@@ -0,0 +1,158 @@
+package validator
+
+import (
+	"testing"
+
+	"apskel-pos-be/internal/constants"
+	"apskel-pos-be/internal/contract"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+)
+
+func TestExpenseValidatorCreateRequiresItemName(t *testing.T) {
+	v := NewExpenseValidator()
+
+	req := &contract.CreateExpenseRequest{
+		Receiver:        "Cashier",
+		TransactionDate: "2026-05-29",
+		CodeNumber:      "EXP-001",
+		OutletID:        uuid.NewString(),
+		Total:           10000,
+		Items: []contract.CreateExpenseItemRequest{
+			{
+				ChartOfAccountID: uuid.NewString(),
+				Amount:           10000,
+			},
+		},
+	}
+
+	err, code := v.ValidateCreateExpenseRequest(req)
+
+	require.Error(t, err)
+	require.Equal(t, constants.MissingFieldErrorCode, code)
+	require.Contains(t, err.Error(), "item 0: item is required")
+}
+
+func TestExpenseValidatorCreateDoesNotRequireHeaderExpenseName(t *testing.T) {
+	v := NewExpenseValidator()
+
+	req := &contract.CreateExpenseRequest{
+		Receiver:        "Cashier",
+		TransactionDate: "2026-05-29",
+		CodeNumber:      "EXP-001",
+		OutletID:        uuid.NewString(),
+		Total:           10000,
+		Items: []contract.CreateExpenseItemRequest{
+			{
+				ChartOfAccountID: uuid.NewString(),
+				Item:             "Cleaning supplies",
+				Amount:           10000,
+			},
+		},
+	}
+
+	err, code := v.ValidateCreateExpenseRequest(req)
+
+	require.NoError(t, err)
+	require.Empty(t, code)
+}
+
+func TestExpenseValidatorCreateAllowsValidOptionalStatus(t *testing.T) {
+	v := NewExpenseValidator()
+	status := "approved"
+
+	req := &contract.CreateExpenseRequest{
+		Receiver:        "Cashier",
+		TransactionDate: "2026-05-29",
+		CodeNumber:      "EXP-001",
+		OutletID:        uuid.NewString(),
+		Status:          &status,
+		Total:           10000,
+		Items: []contract.CreateExpenseItemRequest{
+			{
+				ChartOfAccountID: uuid.NewString(),
+				Item:             "Cleaning supplies",
+				Amount:           10000,
+			},
+		},
+	}
+
+	err, code := v.ValidateCreateExpenseRequest(req)
+
+	require.NoError(t, err)
+	require.Empty(t, code)
+}
+
+func TestExpenseValidatorCreateRejectsInvalidStatus(t *testing.T) {
+	v := NewExpenseValidator()
+	status := "cancelled"
+
+	req := &contract.CreateExpenseRequest{
+		Receiver:        "Cashier",
+		TransactionDate: "2026-05-29",
+		CodeNumber:      "EXP-001",
+		OutletID:        uuid.NewString(),
+		Status:          &status,
+		Total:           10000,
+		Items: []contract.CreateExpenseItemRequest{
+			{
+				ChartOfAccountID: uuid.NewString(),
+				Item:             "Cleaning supplies",
+				Amount:           10000,
+			},
+		},
+	}
+
+	err, code := v.ValidateCreateExpenseRequest(req)
+
+	require.Error(t, err)
+	require.Equal(t, constants.MalformedFieldErrorCode, code)
+	require.Contains(t, err.Error(), "status must be one of: draft, sent, approved, cancel")
+}
+
+func TestExpenseValidatorUpdateRejectsEmptyItemNameWhenProvided(t *testing.T) {
+	v := NewExpenseValidator()
+	empty := " "
+
+	req := &contract.UpdateExpenseRequest{
+		Items: []contract.UpdateExpenseItemRequest{
+			{Item: &empty},
+		},
+	}
+
+	err, code := v.ValidateUpdateExpenseRequest(req)
+
+	require.Error(t, err)
+	require.Equal(t, constants.MalformedFieldErrorCode, code)
+	require.Contains(t, err.Error(), "item 0: item cannot be empty")
+}
+
+func TestExpenseValidatorUpdateRejectsInvalidStatus(t *testing.T) {
+	v := NewExpenseValidator()
+	status := "cancelled"
+
+	req := &contract.UpdateExpenseRequest{Status: &status}
+
+	err, code := v.ValidateUpdateExpenseRequest(req)
+
+	require.Error(t, err)
+	require.Equal(t, constants.MalformedFieldErrorCode, code)
+	require.Contains(t, err.Error(), "status must be one of: draft, sent, approved, cancel")
+}
+
+func TestExpenseValidatorListRejectsInvalidStatus(t *testing.T) {
+	v := NewExpenseValidator()
+
+	req := &contract.ListExpenseRequest{
+		Page:   1,
+		Limit:  10,
+		Status: "cancelled",
+	}
+
+	err, code := v.ValidateListExpenseRequest(req)
+
+	require.Error(t, err)
+	require.Equal(t, constants.MalformedFieldErrorCode, code)
+	require.Contains(t, err.Error(), "status must be one of: draft, sent, approved, cancel")
+}

internal/validator/purchase_order_validator.go

@@ -47,19 +47,20 @@ func (v *PurchaseOrderValidatorImpl) ValidateCreatePurchaseOrderRequest(req *con
 		return errors.New("transaction_date must be in YYYY-MM-DD format"), constants.MalformedFieldErrorCode
 	}
 
-	// Validate due date
-	if strings.TrimSpace(req.DueDate) == "" {
-		return errors.New("due_date is required"), constants.MissingFieldErrorCode
+	if req.DueDate != nil {
+		if strings.TrimSpace(*req.DueDate) == "" {
+			return errors.New("due_date cannot be empty"), constants.MalformedFieldErrorCode
 		}
-	dueDate, err := time.Parse("2006-01-02", req.DueDate)
+
+		dueDate, err := time.Parse("2006-01-02", *req.DueDate)
 		if err != nil {
 			return errors.New("due_date must be in YYYY-MM-DD format"), constants.MalformedFieldErrorCode
 		}
 
-	// Check if due date is after transaction date
 		if dueDate.Before(transactionDate) {
 			return errors.New("due_date must be after transaction_date"), constants.MalformedFieldErrorCode
 		}
+	}
 
 	if req.Reference != nil && len(*req.Reference) > 100 {
 		return errors.New("reference must be at most 100 characters"), constants.MalformedFieldErrorCode
@@ -100,24 +101,29 @@ func (v *PurchaseOrderValidatorImpl) ValidateUpdatePurchaseOrderRequest(req *con
 		}
 	}
 
-	// Validate dates if both are provided
-	if req.TransactionDate != nil && req.DueDate != nil {
-		if *req.TransactionDate != "" && *req.DueDate != "" {
-			transactionDate, err := time.Parse("2006-01-02", *req.TransactionDate)
+	var transactionDate *time.Time
+	if req.TransactionDate != nil && *req.TransactionDate != "" {
+		parsedDate, err := time.Parse("2006-01-02", *req.TransactionDate)
 		if err != nil {
 			return errors.New("transaction_date must be in YYYY-MM-DD format"), constants.MalformedFieldErrorCode
 		}
+		transactionDate = &parsedDate
+	}
+
+	if req.DueDate != nil {
+		if strings.TrimSpace(*req.DueDate) == "" {
+			return errors.New("due_date cannot be empty"), constants.MalformedFieldErrorCode
+		}
 
 		dueDate, err := time.Parse("2006-01-02", *req.DueDate)
 		if err != nil {
 			return errors.New("due_date must be in YYYY-MM-DD format"), constants.MalformedFieldErrorCode
 		}
 
-			if dueDate.Before(transactionDate) {
+		if transactionDate != nil && dueDate.Before(*transactionDate) {
 			return errors.New("due_date must be after transaction_date"), constants.MalformedFieldErrorCode
 		}
 	}
-	}
 
 	if req.Reference != nil && len(*req.Reference) > 100 {
 		return errors.New("reference must be at most 100 characters"), constants.MalformedFieldErrorCode

internal/validator/purchase_order_validator_test.go

@@ -0,0 +1,62 @@
+package validator
+
+import (
+	"testing"
+
+	"apskel-pos-be/internal/constants"
+	"apskel-pos-be/internal/contract"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+)
+
+func validCreatePurchaseOrderRequest() *contract.CreatePurchaseOrderRequest {
+	return &contract.CreatePurchaseOrderRequest{
+		VendorID:        uuid.New(),
+		PONumber:        "PO-001",
+		TransactionDate: "2026-05-29",
+		Items: []contract.CreatePurchaseOrderItemRequest{
+			{
+				IngredientID: uuid.New(),
+				Quantity:     1,
+				UnitID:       uuid.New(),
+				Amount:       1000,
+			},
+		},
+	}
+}
+
+func TestPurchaseOrderValidatorCreateAllowsMissingDueDate(t *testing.T) {
+	validator := NewPurchaseOrderValidator()
+
+	err, code := validator.ValidateCreatePurchaseOrderRequest(validCreatePurchaseOrderRequest())
+
+	require.NoError(t, err)
+	require.Empty(t, code)
+}
+
+func TestPurchaseOrderValidatorCreateRejectsInvalidDueDate(t *testing.T) {
+	validator := NewPurchaseOrderValidator()
+	req := validCreatePurchaseOrderRequest()
+	dueDate := "29-05-2026"
+	req.DueDate = &dueDate
+
+	err, code := validator.ValidateCreatePurchaseOrderRequest(req)
+
+	require.Error(t, err)
+	require.Equal(t, constants.MalformedFieldErrorCode, code)
+	require.Contains(t, err.Error(), "due_date must be in YYYY-MM-DD format")
+}
+
+func TestPurchaseOrderValidatorCreateRejectsDueDateBeforeTransactionDate(t *testing.T) {
+	validator := NewPurchaseOrderValidator()
+	req := validCreatePurchaseOrderRequest()
+	dueDate := "2026-05-28"
+	req.DueDate = &dueDate
+
+	err, code := validator.ValidateCreatePurchaseOrderRequest(req)
+
+	require.Error(t, err)
+	require.Equal(t, constants.MalformedFieldErrorCode, code)
+	require.Contains(t, err.Error(), "due_date must be after transaction_date")
+}

migrations/000074_make_purchase_order_due_date_nullable.down.sql

@@ -0,0 +1,6 @@
+UPDATE purchase_orders
+SET due_date = transaction_date
+WHERE due_date IS NULL;
+
+ALTER TABLE purchase_orders
+    ALTER COLUMN due_date SET NOT NULL;

migrations/000074_make_purchase_order_due_date_nullable.up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE purchase_orders
+    ALTER COLUMN due_date DROP NOT NULL;