refactor: define typescript type for SetRegularKey transaction (#1548)

* refactor: define typescript type for SetRegularKey transaction

test/models/setRegularKey.ts

@@ -0,0 +1,42 @@
+import { ValidationError } from 'xrpl-local/common/errors'
+import { verifySetRegularKey } from './../../src/models/transactions/setRegularKey'
+import { assert } from 'chai'
+
+/**
+ * SetRegularKey Transaction Verification Testing
+ *
+ * Providing runtime verification testing for each specific transaction type
+ */
+describe('SetRegularKey Transaction Verification', function () {
+    let account 
+
+    beforeEach(() => {
+        account = {
+            TransactionType : "SetRegularKey",
+            Account : "rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn",
+            Fee : "12",
+            Flags : 0,
+            RegularKey : "rAR8rR8sUkBoCZFawhkWzY4Y5YoyuznwD"
+        } as any
+    })
+
+    it (`verifies valid SetRegularKey`, () => {
+        assert.doesNotThrow(() => verifySetRegularKey(account))
+    })
+
+    it (`verifies w/o SetRegularKey`, () => {
+        account.RegularKey = undefined
+        assert.doesNotThrow(() => verifySetRegularKey(account))
+    })
+
+    it (`throws w/ invalid RegularKey`, () => {
+        account.RegularKey = 12369846963
+
+        assert.throws(
+            () => verifySetRegularKey(account),
+            ValidationError,
+            "SetRegularKey: RegularKey must be a string"
+        )
+    })
+
+})