Add CHECK-SOURCE-HIGHLIGHTED to file check utils. (#39692)
Summary:
Enhance FileCheck util to check for highlighted source ranges. This is useful when writing tests regarding generated error messages that require source code highlighting.
Here is how the error looks like in different cases:
- In case of needed source code token not found at all in input string:
```
RuntimeError: Expected to find "invalid_token" but did not find it
Searched string:
... <--- HERE
def to_list_missing_type_annotation(x):
# type: (torch.Tensor) -> List[float]
From CHECK-SOURCE-HIGHLIGHTED: invalid_token
```
- In case of source code token not highlighted:
```
Traceback (most recent call last):
File "test_range.py", line 11, in <module>
FileCheck().check_source_highlighted("x.tolist()").run(s)
RuntimeError: Expected to find "~~~~~~~~~~" but did not find it
Searched string:
# type: (torch.Tensor) -> List[float]
li = x.tolist()
~~~~~~~~~ <--- HERE
~~~~~~~~~~~~~~~~~~~... <--- HERE
return li
```
It is a bit confusing since both input text (usually an error message) and generated error messages have their highlighted portions, but this is consistent of previous behavior. Another option is to generate plain error messages without additional range highlighting on input text.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39692
Test Plan:
Added unit test.
Closes https://github.com/pytorch/pytorch/issues/38698
Differential Revision: D22001765
Pulled By: gmagogsfm
fbshipit-source-id: 6681441eee5853ab061d198ccfe55ebffddca202
