FailsWith (Spock Framework API Documentation (2.2))

```
@Retention(RUNTIME)
@Target({METHOD,TYPE})
public @interface FailsWith
```
Indicates that a feature method is expected to fail with the given exception. Useful for pinpointing bugs until they get fixed, or as a replacement for exception conditions in certain corner cases where they cannot be used (like specifying the behavior of exception conditions). In all other cases, exception conditions are preferable.
Applying this annotation to a specification has the same effect as applying it to all feature methods that aren't already annotated with @FailsWith.

- Required Element Summary
  
  Required Elements
  Modifier and Type Required Element Description
  
  Class<? extends Throwable> value
  The expected exception type.
- Optional Element Summary
  
  Optional Elements
  Modifier and Type Optional Element Description
  
  String reason
  The reason for the failure.

- Element Detail
  - value
```
Class<? extends Throwable> value
```
    The expected exception type.
    
    Returns:
    
    the expected exception type
- - reason
```
String reason
```
    The reason for the failure.
    
    Returns:
    
    the reason for the failure
    
    Default:
    
    "unknown"