Validate tool does not PASS a bundle with a single-character filename

[c-suh]

Describe the bug
Validator is failing a bundle which has a file whose name is one character long. Node POC believes this is a side effect of the regular expression enforcing that the filename not begin or end with a dash, underscore, or period.

To Reproduce
Steps to reproduce the behavior:

1. Run validate tool on files inside
   gbo_ast_fieber-beyer_spectra_v2.0_20210211.zip

Expected behavior
1 product will fail with the following:

FAIL: /gbo_ast_fieber-beyer_spectra_v2.0_20210211_aip_v1.0.xml
Begin Content Validation: /gbo_ast_fieber-beyer_spectra_v2.0_20210211_transfer_manifest_v1.0.tab
ERROR [error.table.field_value_data_type_mismatch] table 1, record 129, field 2: Value does not match its data type 'ASCII_File_Specification_Name': The filename spec '6.xml' does not match the pattern '[A-Za-z0-9][A-Za-z0-9-.][A-Za-z0-9].[A-Za-z0-9]+'
ERROR [error.table.field_value_data_type_mismatch] table 1, record 130, field 2: Value does not match its data type 'ASCII_File_Specification_Name': The filename spec '6.tab' does not match the pattern '[A-Za-z0-9][A-Za-z0-9-.][A-Za-z0-9].[A-Za-z0-9]+'
End Content Validation: /gbo_ast_fieber-beyer_spectra_v2.0_20210211_transfer_manifest_v1.0.tab

Version of Software Used
Version 1.23.1

Test Data / Additional context
Bug discovered while attempting to validate one of multiple bundles submitted in NASA-PDS/operations#61. List of filename rules was provided in NASA-PDS/operations#61 (comment).

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):
Not on local desktop; run on pds-gamma.

Applicable requirements
? but I like the unicorns, so I'm leaving them
: unicorn: # 1
: unicorn: # 2

[jordanpadams]

@c-suh per comment above 😆

[qchaupds]

The pattern for filename is defined in src/main/java/gov/nasa/pds/tools/validate/content/table/FieldValueValidator.java
and it seems to required at least two characters:

private static final Pattern asciiFileNamePattern = Pattern.compile(
"[A-Za-z0-9][A-Za-z0-9-_\.]*[A-Za-z0-9]\.[A-Za-z0-9]+");

A better pattern may be:

"[A-Za-z0-9] a star should be here [A-Za-z0-9-_\.]*[A-Za-z0-9]\.[A-Za-z0-9]+")

to accept file name with just one character.

[qchaupds]

With the better name pattern in place, a run of valid label provided by user accepts the single-character filename:

% validate -R pds4.label -r report_github299_label_valid.json -s json -t src/test/resources/github299/valid/gbo_ast_fieber-beyer_spectra
_v2.0_20210211_aip_v1.0.xml

% egrep "status|label" report_github299_label_valid.json
"ruleType": "pds4.label",
"status": "PASS",
"label": "file:/home/qchau/sandbox/validate/src/test/resources/github299/valid/gbo_ast_fieber-beyer_spectra_v2.0_20210211_aip_v1.0.xml",

Running against a label that points to 'bad' file names, resulted in correct error messages:

% validate -R pds4.label -r report_github299_label_invalid.json -s json -t src/test/resources/github299/invalid/gbo_ast_fieber-beyer_spect
ra_v2.0_20210211_aip_v1.0.xml

File names should not end with '_' before the dot.

% grep message report_github299_label_invalid.json | grep ASCII_File_Specification_Name
"message": "Value does not match its data type 'ASCII_File_Specification_Name': The filename spec '158_.xml' does not match the pattern '[A-Za-z0-9][A-Za-z0-9-_\.][A-Za-z0-9]\.[A-Za-z0-9]+'"
"message": "Value does not match its data type 'ASCII_File_Specification_Name': The filename spec '158_.tab' does not match the pattern '[A-Za-z0-9][A-Za-z0-9-_\.][A-Za-z0-9]\.[A-Za-z0-9]+'"
"message": "Value does not match its data type 'ASCII_File_Specification_Name': The filename spec '.tab' does not match the pattern '[A-Za-z0-9]*[A-Za-z0-9-\.]*[A-Za-z0-9]\.[A-Za-z0-9]+'"

[jordanpadams]

closed per #306