coduo/php-matcher — pull request #19 by RobinvdVleuten (2014-06-19 11:42:25+00:00)
Title: A null value can be matched.

Hi there,

When testing my JSON OAuth responses, I tried to compare with the following pattern;
```json
{
"access_token": @string@,
"expires_in": 3600,
"token_type": "bearer",
"scope": null,
"refresh_token": @string@
}
```

Which gave me the error `There is no element under path [scope] in pattern.`.

To fix this, I came up with a NullMatcher so that the following pattern can be used;
```json
{
"access_token": @string@,
"expires_in": 3600,
"token_type": "bearer",
"scope": @null@,
"refresh_token": @string@
}
```