fix: add a check to ensure Jest doesn't throw error. closes #644

Author: satya164

src/components/Switch.js

@@ -7,7 +7,9 @@ import setColor from 'color';
 import { withTheme } from '../core/theming';
 import type { Theme } from '../types';
 
-const version = NativeModules.PlatformConstants.reactNativeVersion;
+const version = NativeModules.PlatformConstants
+  ? NativeModules.PlatformConstants.reactNativeVersion
+  : undefined;
 
 type Props = React.ElementProps<NativeSwitch> & {
   /**
@@ -124,7 +126,7 @@ class Switch extends React.Component<Props> {
               : grey50;
 
     const props =
-      version.major === 0 && version.minor <= 56
+      version && version.major === 0 && version.minor <= 56
         ? {
             onTintColor,
             thumbTintColor,

src/components/__tests__/Switch.test.js

@@ -0,0 +1,30 @@
+/* @flow */
+
+import * as React from 'react';
+import renderer from 'react-test-renderer';
+import Switch from '../Switch';
+import { pink500 } from '../../styles/colors';
+
+it('renders on switch', () => {
+  const tree = renderer.create(<Switch value />).toJSON();
+
+  expect(tree).toMatchSnapshot();
+});
+
+it('renders off switch', () => {
+  const tree = renderer.create(<Switch value={false} />).toJSON();
+
+  expect(tree).toMatchSnapshot();
+});
+
+it('renders disabled switch', () => {
+  const tree = renderer.create(<Switch disabled value />).toJSON();
+
+  expect(tree).toMatchSnapshot();
+});
+
+it('renders switch with color', () => {
+  const tree = renderer.create(<Switch value color={pink500} />).toJSON();
+
+  expect(tree).toMatchSnapshot();
+});

src/components/__tests__/__snapshots__/Switch.test.js.snap

@@ -0,0 +1,66 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`renders disabled switch 1`] = `
+<RCTSwitch
+  disabled={true}
+  onChange={[Function]}
+  onResponderTerminationRequest={[Function]}
+  onStartShouldSetResponder={[Function]}
+  onTintColor="#03dac4"
+  style={
+    Object {
+      "height": 31,
+      "width": 51,
+    }
+  }
+  value={true}
+/>
+`;
+
+exports[`renders off switch 1`] = `
+<RCTSwitch
+  onChange={[Function]}
+  onResponderTerminationRequest={[Function]}
+  onStartShouldSetResponder={[Function]}
+  onTintColor="#03dac4"
+  style={
+    Object {
+      "height": 31,
+      "width": 51,
+    }
+  }
+  value={false}
+/>
+`;
+
+exports[`renders on switch 1`] = `
+<RCTSwitch
+  onChange={[Function]}
+  onResponderTerminationRequest={[Function]}
+  onStartShouldSetResponder={[Function]}
+  onTintColor="#03dac4"
+  style={
+    Object {
+      "height": 31,
+      "width": 51,
+    }
+  }
+  value={true}
+/>
+`;
+
+exports[`renders switch with color 1`] = `
+<RCTSwitch
+  onChange={[Function]}
+  onResponderTerminationRequest={[Function]}
+  onStartShouldSetResponder={[Function]}
+  onTintColor="#e91e63"
+  style={
+    Object {
+      "height": 31,
+      "width": 51,
+    }
+  }
+  value={true}
+/>
+`;