Question

I’m trying to create a custom Checkstyle rule which will flag as an error when developers use @Ignore without a comment. Therefore I’m looking for a regular expression which matches the following scenario:

@Ignore
@Test
public void someTest() {
   ...
}

and this one:

@Ignore @Test    //or @Test @Ignore
public void someTest() {
   ...
}

but would not match this scenario:

@Ignore("some comment detailing why this test was ignored")
@Test
public void someTest() {
   ...
}

or this one:

@Test
public void someTest() {
   ...
}

So basically its a regular expression matching @Ignore but only when its present and only when its present without qualifying comments, e.g. @Ignore("commnent here")

Answer 1

@Ignore(?![ \t]*\()

matches @Ignore only if it’s not followed by an opening parenthesis.

Explanation:

@Ignore   # Match "@Ignore"
(?!       # Assert that we can't match...
 [ \t]*   # optional spaces/tabs
 \(       # followed by a ( at the current position
)         # End of lookahead

In Java:

Pattern regex = Pattern.compile("@Ignore(?![ \\t]*\\()");