@TempDir Path tempDir;

@Test
void testReadCustomerFile() throws IOException {
    Path inputFile = tempDir.resolve("CUSTFILE.txt");
    Files.write(inputFile, List.of(buildCustomerRecord("00001", "John Smith")));

    List<CustomerRecord> customers = FileHelpers.readCustomerFile(inputFile.toString());
    assertEquals(1, customers.size());
    assertEquals("John Smith", customers.get(0).getName());
}

@Test
void testProcessorGeneratesReport() throws IOException {
    Path custFile = tempDir.resolve("CUSTFILE.txt");
    Path reportFile = tempDir.resolve("REPORT.txt");
    createTestFiles(custFile);

    Psam1 processor = Psam1.createFromFiles(custFile.toString(), reportFile.toString());
    processor.execute();

    String report = Files.readString(reportFile);
    assertAll("Report validation",
        () -> assertTrue(report.contains("CUSTOMER REPORT")),
        () -> assertTrue(report.contains("STATISTICAL SUMMARY"))
    );
}

<!-- Integration tests with failsafe plugin -->
<plugin>
    <artifactId>maven-failsafe-plugin</artifactId>
    <version>3.2.3</version>
    <configuration>
        <includes><include>**/*IntegrationTest.java</include></includes>
    </configuration>
</plugin>

mvn verify   # Runs both unit and integration tests