test(account): cover missing picker business date

src/test/java/com/lab/labtimesheet/feature/account/service/EligibleInternOptionIntegrationTest.java

@@ -1,6 +1,7 @@
 package com.lab.labtimesheet.feature.account.service;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import java.sql.Timestamp;
 import java.time.Instant;
@@ -83,6 +84,13 @@ class EligibleInternOptionIntegrationTest {
         assertThat(options).extracting(EligibleInternOption::userId).doesNotHaveDuplicates();
     }
 
+    @Test
+    void rejectsMissingBusinessDate() {
+        assertThatThrownBy(() -> accounts.eligibleInternOptions(null))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Business date is required");
+    }
+
     private long activeIntern(String displayName, String studentCode, LocalDate startDate, LocalDate endDate) {
         long userId = activeUser(GlobalRole.INTERN, displayName);
         activeProfile(userId, studentCode, startDate, endDate);