expect.installTheme(...)

Install a MagicPen theme into the expect instance, so that it's used when rendering error messages and diffs.

Proxies through to magicPen.installTheme. See the documentation there.

Example:

expect.installTheme({
  styles: {
    ugliness: 'yellow',
    jsKeyword: 'ugliness',
  },
});
 
expect(function foo() {}, 'to throw', 'bar');

expected function foo() {} to throw 'bar'
  
expected function foo() {} to throw
  
did not throw