Catch IndexError when getting dir creation date

Description

Index error means that there are no files in the directory. We catch this error, as we want get_dir_creation_date to raise only a ValueError, which highlights better that the provided run is incorrect.

Previous changes broke the tests.

How Has This Been Tested?

pytest -vv tests/test_cal_tools.py

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

Reviewers

cal_tools/cal_tools/tools.py

@@ -273,7 +273,7 @@ def get_dir_creation_date(directory: str, run: int,
                 cdate = fin['METADATA/creationDate'][0].decode()
                 cdate = datetime.datetime.strptime(cdate, "%Y%m%dT%H%M%SZ")
             return cdate
-        except (IOError, ValueError):
+        except (IndexError, IOError, ValueError):
             ntries -= 1
         except KeyError:  # The files are here, but it's an older dataset
             return datetime.datetime.fromtimestamp(directory.stat().st_ctime)