Drop MuiThemeProvider from the tests.

__tests__/testIcons.js

@@ -1,19 +1,14 @@
 /* eslint-env jest */
 import React from 'react'
 import renderer from 'react-test-renderer'
-import MuiThemeProvider from '@material-ui/core/styles/MuiThemeProvider'
 import * as commonjsIcons from '../package/index'
 import * as es2015Icons from '../package/index.es'
 
 describe('the generated commonjs module', () => {
   for (const iconName of Object.keys(commonjsIcons)) {
     it(`should export a ${iconName} element that returns an SVG`, () => {
       const Icon = commonjsIcons[iconName]
-      const renderedIcon = renderer.create((
-        <MuiThemeProvider>
-          <Icon />
-        </MuiThemeProvider>
-      )).toJSON()
+      const renderedIcon = renderer.create(<Icon />).toJSON()
       expect(renderedIcon.type).toBe('svg')
     })
   }
@@ -23,11 +18,7 @@ describe('the generated es2015 module', () => {
   for (const iconName of Object.keys(es2015Icons)) {
     it(`should export a ${iconName} element that returns an SVG`, () => {
       const Icon = es2015Icons[iconName]
-      const renderedIcon = renderer.create((
-        <MuiThemeProvider>
-          <Icon />
-        </MuiThemeProvider>
-      )).toJSON()
+      const renderedIcon = renderer.create(<Icon />).toJSON()
       expect(renderedIcon.type).toBe('svg')
     })
   }