Add explicit normalizer test (#2730)

* Add explicit normalizer test

* More expansive

* nested

packages/rpc-core/src/normalizer.spec.ts

@@ -0,0 +1,30 @@
+// Copyright 2017-2020 @polkadot/rpc-core authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import normalizer from './normalizer';
+
+describe('normalizer', (): void => {
+  it('works when BigInt is in the data (object)', (): void => {
+    expect(
+      normalizer('instance')({ a: 'bar', b: 1234567890987654321n, c: 123 })
+    ).toEqual('instance{"a":"bar","b":"1234567890987654321","c":123}');
+  });
+
+  it('works when BigInt is in the data (array)', (): void => {
+    expect(
+      normalizer('instance')(['bar', 1234567890987654321n, 123])
+    ).toEqual('instance["bar","1234567890987654321",123]');
+  });
+
+  it('works when BigInt is in the data (single)', (): void => {
+    expect(
+      normalizer('instance')(1234567890987654321n)
+    ).toEqual('instance"1234567890987654321"');
+  });
+
+  it('works when BigInt is in the data (nested)', (): void => {
+    expect(
+      normalizer('instance')({ a: 'bar', b: { foo: 1234567890987654321n }, c: 123 })
+    ).toEqual('instance{"a":"bar","b":{"foo":"1234567890987654321"},"c":123}');
+  });
+});