Add log tests

utils/app/log/__tests__/log.test.js

@@ -0,0 +1,24 @@
+import log from '../';
+
+const data = {
+  string: 'string',
+  number: 1,
+  object: {
+    foo: 'bar',
+  },
+  array: ['foo', 'bar'],
+};
+
+it('should return the descriptor and data being logged as strings', () => {
+  expect(log('test', data)).toEqual({
+    descriptor: 'test',
+    data: JSON.stringify(data),
+  });
+});
+
+it('should return the descriptor and no data if no data is being logged', () => {
+  expect(log('test', null)).toEqual({
+    descriptor: 'test',
+    data: JSON.stringify(null),
+  });
+});