refactor: define SignerListSet model and tests (#1538)

* define typescript type for SignerListSet transaction

src/models/common/index.ts

@@ -40,3 +40,8 @@ interface PathStep {
 }
 
 export type Path = PathStep[]
+
+export interface SignerEntry {
+  Account: string;
+  SignerWeight: number;
+}

src/models/transactions/index.ts

@@ -3,3 +3,4 @@ export * from './offerCreate'
 export * from './checkCreate'
 export * from './checkCash'
 export * from './checkCancel'
+export * from './signerListSet'

src/models/transactions/signerListSet.ts

@@ -0,0 +1,38 @@
+import { ValidationError } from "../../common/errors"
+import { SignerEntry } from "../common"
+import { BaseTransaction, verifyBaseTransaction } from "./common"
+
+export interface SignerListSet extends BaseTransaction {
+    TransactionType: "SignerListSet"
+    SignerQuorum: number
+    SignerEntries: SignerEntry[]
+}
+
+/**
+ * Verify the form and type of an SignerListSet at runtime.
+ * 
+ * @param tx - An SignerListSet Transaction
+ * @returns - Void.
+ * @throws - When the SignerListSet is Malformed.
+ */
+ export function verifySignerListSet(tx: SignerListSet): void {
+    verifyBaseTransaction(tx)
+
+    if (tx.SignerQuorum === undefined)
+        throw new ValidationError("SignerListSet: missing field SignerQuorum")
+
+    if (typeof tx.SignerQuorum !== 'number')
+        throw new ValidationError("SignerListSet: invalid SignerQuorum")
+
+    if (tx.SignerEntries === undefined)
+        throw new ValidationError("SignerListSet: missing field SignerEntries")
+
+    if (!Array.isArray(tx.SignerEntries))
+        throw new ValidationError("SignerListSet: invalid SignerEntries")
+
+    if (tx.SignerEntries.length === 0)
+        throw new ValidationError("SignerListSet: need atleast 1 member in SignerEntries")
+    
+    if (tx.SignerEntries.length > 8)
+        throw new ValidationError("SignerListSet: maximum of 8 members allowed in SignerEntries")
+}

src/models/transactions/transaction.ts

@@ -3,6 +3,7 @@ import { OfferCreate } from "./offerCreate";
 import { CheckCash } from "./checkCash";
 import { CheckCancel } from "./checkCancel";
 import { CheckCreate } from "./checkCreate";
+import { SignerListSet } from "./signerListSet";
 
 export type Transaction =
 //     AccountSet
@@ -21,7 +22,7 @@ export type Transaction =
 //   | PaymentChannelCreate
 //   | PaymentChannelFund
 //   | SetRegularKey
-//   | SignerListSet
+     | SignerListSet
 //   | TicketCreate
 //   | TrustSet