src/test/java/com/erp/invoice/InvoiceApiApplicationTests.java

package com.erp.invoice;

import com.erp.invoice.model.Invoice;
import com.erp.invoice.repository.InvoiceRepository;
import com.erp.invoice.service.InvoiceService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;

@SpringBootTest
class InvoiceApiApplicationTests {

    @Autowired
    private InvoiceRepository invoiceRepository;

    @Autowired
    private InvoiceService invoiceService;

    @Test
    void contextLoads() {
        // Verifies application context loads successfully
    }

    @Test
    void databaseIsSeeded() {
        long count = invoiceRepository.count();
        assertThat(count).isGreaterThan(0);
    }

    @Test
    void canFetchBySupplierId() {
        var results = invoiceService.getInvoicesBySupplierId("SUP-001");
        assertThat(results).isNotEmpty();
        results.forEach(inv -> assertThat(inv.getSupplierId()).isEqualTo("SUP-001"));
    }

    @Test
    void canFetchByStatus() {
        var results = invoiceService.getInvoicesByStatus(Invoice.InvoiceStatus.PAID);
        assertThat(results).isNotEmpty();
        results.forEach(inv -> assertThat(inv.getStatus()).isEqualTo("PAID"));
    }

    @Test
    void canFetchByInvoiceId() {
        var result = invoiceService.getInvoiceByInvoiceId("INV-2024-0001");
        assertThat(result).isPresent();
        assertThat(result.get().getInvoiceId()).isEqualTo("INV-2024-0001");
    }

    @Test
    void canGenerateSummary() {
        var summary = invoiceService.getSummary();
        assertThat(summary.getTotalInvoices()).isGreaterThan(0);
        assertThat(summary.getCountByStatus()).isNotEmpty();
    }
}