chore: fix test flakiness and add mock helper (#10956)

web3.js/test/mockrpc/confirm-transaction.js

@@ -0,0 +1,31 @@
+// @flow
+
+import type {TransactionSignature} from '../../src/transaction';
+import {url} from '../url';
+import {mockRpc} from '../__mocks__/node-fetch';
+
+export function mockConfirmTransaction(signature: TransactionSignature) {
+  mockRpc.push([
+    url,
+    {
+      method: 'getSignatureStatuses',
+      params: [[signature]],
+    },
+    {
+      error: null,
+      result: {
+        context: {
+          slot: 11,
+        },
+        value: [
+          {
+            slot: 0,
+            confirmations: null,
+            status: {Ok: null},
+            err: null,
+          },
+        ],
+      },
+    },
+  ]);
+}