Consider empty/blank as empty string instead of null for CSV/XML/Excel data provider and BDD examples

[cjayswal]

Scenario 2:
Cannot leave a variable value empty String in the csv. It takes null and not a whitespace value which was the case earlier.

summary,file-format,with-data,amount-rows
one valid email address (XLSX),xlsx,,1

This variable is not even set for the test:
And generate 'xlsx' into file 'fileName' for '1' users and profiles with data '{${with-data}}'[0.005s ]

Report looks like this:
And generate 'xlsx' into file 'fileName' for '1' users and profiles with data '{${with-data}}'[0.005s ]
Unable to invoke JavaStep with given arguments: generateBulkUserProfileWithData[xlsx, fileName, 1, {${with-data}}]
at

Workaround:
As of now based on your implementation code, I've added \ followed by a comma at the end for every line in the csv so that we can use the older implementation code:

summary,file-format,with-data,amount-rows
one valid email address (XLSX),xlsx,,1,,

This was working fine in 2.14-RC1

This behavior is as per design with 2.1.14+ available from 2.1.14-RC3. Refer release notes from 2.1.14-RC3 Updated CSV, XML and Excel data provider to return objects instead of Strings

Originally posted by @cjayswal in #335 (comment)