Add tests

packages/util/src/hex/toString.spec.ts

@@ -0,0 +1,19 @@
+// Copyright 2017-2019 @polkadot/util authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { hexToString } from '.';
+
+describe('hexToString', (): void => {
+  it('converts an empty to ""', (): void => {
+    expect(
+      hexToString()
+    ).toEqual('');
+  });
+
+  it('converts to a string from hex', (): void => {
+    expect(
+      hexToString('0x68656c6c6f')
+    ).toEqual('hello');
+  });
+});

packages/util/src/string/toHex.spec.ts

@@ -0,0 +1,19 @@
+// Copyright 2017-2019 @polkadot/util authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { stringToHex } from '.';
+
+describe('hexToString', (): void => {
+  it('converts an empty to ""', (): void => {
+    expect(
+      stringToHex()
+    ).toEqual('0x');
+  });
+
+  it('converts to a hex from string', (): void => {
+    expect(
+      stringToHex('hello')
+    ).toEqual('0x68656c6c6f');
+  });
+});