Add tests for utilities (#23989)

Summary:
This PR add tests for several utilities in `Libraries/Utilities`, as a follow-up of #23903.

The following utilities are now tested:
* `clamp.js`
* `binareToBase64.js`
* `DeviceInfo.js`
* `mergeIntoFast.js`
* `PixelRatio.js`
* `infoLog.js`
* `logError.js`
* `warnOnce.js`
* `mapWithSeparator` (added a missing test)

Not applicable, since it only adds tests.
Pull Request resolved: https://github.com/facebook/react-native/pull/23989

Differential Revision: D14502806

Pulled By: cpojer

fbshipit-source-id: e2c3b3a35f4f765d5336b998ab92dba14eeac7bc

Libraries/Utilities/__tests__/DeviceInfo-test.js

@@ -0,0 +1,19 @@
+/**
+ * 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';
+
+describe('DeviceInfo', () => {
+  const DeviceInfo = require('DeviceInfo');
+
+  it('should give device info', () => {
+    expect(DeviceInfo).toHaveProperty('Dimensions');
+  });
+});

Libraries/Utilities/__tests__/PixelRatio-test.js

@@ -0,0 +1,52 @@
+/**
+ * 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';
+
+describe('PixelRatio', () => {
+  const Dimensions = require('Dimensions');
+  const PixelRatio = require('PixelRatio');
+
+  beforeEach(() => {
+    Dimensions.set({
+      windowPhysicalPixels: {
+        width: 400,
+        height: 800,
+        scale: 2,
+        fontScale: 3,
+      },
+    });
+  });
+
+  it('should give the pixel density', () => {
+    expect(PixelRatio.get()).toEqual(2);
+  });
+
+  it('should give the font scale when present', () => {
+    expect(PixelRatio.getFontScale()).toEqual(3);
+  });
+
+  it('should give the pixel density instead of the font scale when the front scale is not present', () => {
+    Dimensions.set({
+      windowPhysicalPixels: {
+        scale: 2,
+      },
+    });
+    expect(PixelRatio.getFontScale()).toEqual(2);
+  });
+
+  it('should convert a layout size to pixel size', () => {
+    expect(PixelRatio.getPixelSizeForLayoutSize(400)).toEqual(800);
+  });
+
+  it('should round a layout size to pixel size', () => {
+    expect(PixelRatio.roundToNearestPixel(8.4)).toEqual(8.5);
+  });
+});

Libraries/Utilities/__tests__/binaryToBase64-test.js

@@ -0,0 +1,48 @@
+/**
+ * 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 base64 = require('base64-js');
+const {TextEncoder, TextDecoder} = require('util');
+
+describe('binaryToBase64', () => {
+  const binaryToBase64 = require('binaryToBase64');
+
+  it('should encode a Uint8Array', () => {
+    const input = new TextEncoder().encode('Test string');
+
+    expect(base64ToString(binaryToBase64(input))).toEqual('Test string');
+  });
+
+  it('should encode an ArrayBuffer', () => {
+    const input = new TextEncoder().encode('Test string').buffer;
+
+    expect(base64ToString(binaryToBase64(input))).toEqual('Test string');
+  });
+
+  it('should encode a DataView', () => {
+    const input = new DataView(new TextEncoder().encode('Test string').buffer);
+
+    expect(base64ToString(binaryToBase64(input))).toEqual('Test string');
+  });
+
+  it('should not encode a non ArrayBuffer or non typed array', () => {
+    const input = ['i', 'n', 'v', 'a', 'l', 'i', 'd'];
+
+    expect(() => binaryToBase64(input)).toThrowError();
+  });
+});
+
+function base64ToString(base64String) {
+  const byteArray = base64.toByteArray(base64String);
+
+  return new TextDecoder().decode(byteArray);
+}

Libraries/Utilities/__tests__/clamp-test.js

@@ -0,0 +1,32 @@
+/**
+ * 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';
+
+describe('clamp', () => {
+  const clamp = require('clamp');
+
+  it('should return the value if the value does not exceed boundaries', () => {
+    expect(clamp(0, 5, 10)).toEqual(5);
+    expect(clamp(5, 5, 10)).toEqual(5);
+    expect(clamp(0, 5, 5)).toEqual(5);
+    expect(clamp(5, 5, 5)).toEqual(5);
+  });
+
+  it('should return the min value if the value is too low', () => {
+    expect(clamp(10, 5, 20)).toEqual(10);
+    expect(clamp(10, 9, 20)).toEqual(10);
+  });
+
+  it('should return the max value if the value is too high', () => {
+    expect(clamp(10, 25, 20)).toEqual(20);
+    expect(clamp(10, 21, 20)).toEqual(20);
+  });
+});

Libraries/Utilities/__tests__/infoLog-test.js

@@ -0,0 +1,32 @@
+/**
+ * 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';
+
+describe('infoLog', () => {
+  const infoLog = require('infoLog');
+
+  it('logs messages to the console', () => {
+    console.log = jest.fn();
+
+    infoLog('This is a log message');
+
+    expect(console.log).toHaveBeenCalledWith('This is a log message');
+  });
+
+  it('logs messages with multiple arguments to the console', () => {
+    console.log = jest.fn();
+
+    const data = 'log';
+    infoLog('This is a', data, 'message');
+
+    expect(console.log).toHaveBeenCalledWith('This is a', 'log', 'message');
+  });
+});

Libraries/Utilities/__tests__/logError-test.js

@@ -0,0 +1,48 @@
+/**
+ * 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';
+
+describe('logError', () => {
+  const logError = require('logError');
+
+  it('logs error messages to the console', () => {
+    console.error.apply = jest.fn();
+
+    logError('This is a log message');
+
+    expect(console.error.apply).toHaveBeenCalledWith(console, [
+      'This is a log message',
+    ]);
+  });
+
+  it('logs error messages with multiple arguments to the console', () => {
+    console.error.apply = jest.fn();
+
+    const data = 'log';
+    logError('This is a', data, 'message');
+
+    expect(console.error.apply).toHaveBeenCalledWith(console, [
+      'This is a',
+      'log',
+      'message',
+    ]);
+  });
+
+  it('logs errors to the console', () => {
+    console.error = jest.fn();
+
+    logError(new Error('The error message'));
+
+    expect(console.error.mock.calls[0][0]).toContain(
+      'Error: "The error message".  Stack:',
+    );
+  });
+});

Libraries/Utilities/__tests__/mapWithSeparator-test.js

@@ -54,4 +54,18 @@ describe('mapWithSeparator', () => {
     );
     expect(result).toEqual([3, 0, 2, 1, 1]);
   });
+
+  it('mapWithSeparator returns empty array when empty array is given as input', () => {
+    const array = [];
+    const result = mapWithSeparator(
+      array,
+      function(value) {
+        return value * 2;
+      },
+      function() {
+        return 0;
+      },
+    );
+    expect(result).toEqual([]);
+  });
 });

Libraries/Utilities/__tests__/mergeIntoFast-test.js

@@ -0,0 +1,51 @@
+/**
+ * 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';
+
+describe('mergeIntoFast', () => {
+  const mergeIntoFast = require('mergeIntoFast');
+
+  it('should merge two objects', () => {
+    const a = {fontScale: 2, height: 1334};
+    const b = {scale: 2, width: 750};
+
+    mergeIntoFast(a, b);
+
+    expect(a).toEqual({fontScale: 2, height: 1334, scale: 2, width: 750});
+  });
+
+  it('should use the values of the second object if there are duplicate keys', () => {
+    const a = {fontScale: 2};
+    const b = {fontScale: 3};
+
+    mergeIntoFast(a, b);
+
+    expect(a).toEqual({fontScale: 3});
+  });
+
+  it('should merge into an empty object', () => {
+    const a = {};
+    const b = {scale: 2, width: 750};
+
+    mergeIntoFast(a, b);
+
+    expect(a).toEqual({scale: 2, width: 750});
+  });
+
+  it('should merge from an empty object', () => {
+    const a = {scale: 2, width: 750};
+    const b = {};
+
+    mergeIntoFast(a, b);
+
+    expect(a).toEqual({scale: 2, width: 750});
+  });
+});

Libraries/Utilities/__tests__/warnOnce-test.js

@@ -0,0 +1,27 @@
+/**
+ * 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';
+
+describe('warnOnce', () => {
+  const warnOnce = require('warnOnce');
+
+  it('logs warning messages to the console exactly once', () => {
+    console.error = jest.fn();
+
+    warnOnce('test-message', 'This is a log message');
+    warnOnce('test-message', 'This is a second log message');
+
+    expect(console.error).toHaveBeenCalledWith(
+      'Warning: This is a log message',
+    );
+    expect(console.error).toHaveBeenCalledTimes(1);
+  });
+});