I have this regular expression

```
([A-Z], )*

```

which should match something like
`test,` (with a space after the comma)

How to I change the regex expression so that if there are any characters after the space then it doesn't match.
For example if I had:

```
test, test

```

I'm looking to do something similar to

```
([A-Z], ~[A-Z])*

```

Cheers