added a testing class for billers

src/main/java/com/billpaymentservice/bbps/entites/BillValidation.java

@@ -0,0 +1,61 @@
+package com.billpaymentservice.bbps.entites;
+
+
+import java.util.List;
+
+import jakarta.persistence.*;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Table(name = "bill_validation")
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class BillValidation {
+
+    @Id
+    @Column(name = "bill_id", nullable = false, length = 100)
+    private String billId;
+
+    @Column(name = "ref_id", length = 100)
+    private String refId;
+
+    @Column(name = "biller_id", length = 100)
+    private String billerId;
+
+    @Column(name = "status", length = 100)
+    private String status;
+
+    @Column(name = "action_type", length = 100)
+    private String actionType;
+
+    @Column(name = "user_id", length = 100)
+    private String userId;
+
+    @Column(name = "biller_response", columnDefinition = "TEXT")
+    private String billerResponse;
+
+    @Column(name = "additional_info", columnDefinition = "TEXT")
+    private String additionalInfo;
+
+    // 👇 Proper nested customer params (OneToMany)
+    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "bill")
+    private List<CustomerParamBillValidation> customerParams;
+
+    @Column(name = "plan_info_daos", columnDefinition = "TEXT")
+    private String planInfoDaos;
+
+    @Column(name = "creation_date", length = 50)
+    private String creationDate;
+
+    @Column(name = "modified_date", length = 50)
+    private String modifiedDate;
+
+    @Column(name = "created_epoch_date", length = 50)
+    private String createdEpochDate;
+
+    @Column(name = "modified_epoch_date", length = 50)
+    private String modifiedEpochDate;
+}