adding tests for the processColorArray mapping (#27344)

Summary:
The following pull-requests adds test for the `processColorArray` function. This ensures that the mapping is respected even in the `processColor` file changes. It also ensures that the mapping follows the basic expected functionality

## Changelog
[General] [Added] - Add test for the `processColorArray` to make sure it maps correctly
Pull Request resolved: #27344

Test Plan:
- Run `npm run test Libraries/StyleSheet/__tests__/processColorArray-test.js` to ensure tests pass
- Run `npm run lint` to make sure there are no styling conflicts.

<img width="454" alt="Screen Shot 2019-11-26 at 3 24 44 PM" src="https://user-images.githubusercontent.com/31664059/69680816-e8641780-1060-11ea-89ca-336c5534eb16.png">

Differential Revision: D18770069

Pulled By: hramos

fbshipit-source-id: 1a8647931818360b9912dc6fb50c339a91b9d4ea

Libraries/StyleSheet/__tests__/processColorArray-test.js

@@ -0,0 +1,60 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @emails oncall+react_native
+ */
+
+'use strict';
+
+const {OS} = require('../../Utilities/Platform');
+const processColorArray = require('../processColorArray');
+
+const platformSpecific =
+  OS === 'android'
+    ? unsigned => unsigned | 0 //eslint-disable-line no-bitwise
+    : x => x;
+
+describe('processColorArray', () => {
+  describe('predefined color name array', () => {
+    it('should convert array of color name type', () => {
+      const colorFromStringArray = processColorArray(['red', 'white', 'black']);
+      const expectedIntArray = [0xffff0000, 0xffffffff, 0xff000000].map(
+        platformSpecific,
+      );
+      expect(colorFromStringArray).toEqual(expectedIntArray);
+    });
+
+    it('should convert array of color type rgb(x, y, z)', () => {
+      const colorFromRGBArray = processColorArray([
+        'rgb(10, 20, 30)',
+        'rgb(30, 20, 10)',
+        'rgb(50, 150, 250)',
+      ]);
+      const expectedIntArray = [0xff0a141e, 0xff1e140a, 0xff3296fa].map(
+        platformSpecific,
+      );
+      expect(colorFromRGBArray).toEqual(platformSpecific(expectedIntArray));
+    });
+
+    it('should convert array of color type hsl(x, y%, z%)', () => {
+      const colorFromHSLArray = processColorArray([
+        'hsl(318, 69%, 55%)',
+        'hsl(218, 59%, 33%)',
+        'hsl(118, 49%, 22%)',
+      ]);
+      const expectedIntArray = [0xffdb3dac, 0xff234786, 0xff1e541d].map(
+        platformSpecific,
+      );
+      expect(colorFromHSLArray).toEqual(platformSpecific(expectedIntArray));
+    });
+
+    it('should return null if no array', () => {
+      const colorFromNoArray = processColorArray(null);
+      expect(colorFromNoArray).toEqual(null);
+    });
+  });
+});