Byte order mark at the beginning of import groups file fail the process with the confusing error message

Requirements

1. Must be tested on either MySQL or MariaDB

Preparation

1. Download the 4 test CSVs from this issue (test1.csv - test4.csv).

Test 1 - Importing of groups with BOM characters

1. Log in as admin and go to any course.
2. In the cog, select More...
3. Click in Users tab and then Groups.
4. Click Import groups
5. Download attached test1.csv and add to filepicker and then click Import groups button.
6. Make sure two groups are created, Sec1 and Sec2 (click Continue on the confirmation page).
7. Select group Sec1 and then click Edit group settings.
8. Make sure the group description is "SaMW" and does not contain bom chars (SaMW�).

Test 2 - New CSV delimiter field

1. Return to the Groups page, and delete the 2 groups you just created (Sec1 and Sec2).
2. Again, select Import groups to navigate to the group import page.
3. Choose the same file (test1.csv), but this time select semicolon ; in the CSV delimiter field and click Import groups.
4. Make sure you see an error.
5. Now, choose the file test2.csv, select semicolon ; in the CSV delimiter field and click Import groups.
6. Make sure the groups Semicolon1 and Semicolon2 are successfully imported.

Test 3 - New Encoding field

1. Click Continue to return to the group import page.
2. Choose test3.csv, leave CSV delimiter as comma, and Encoding as UTF-8, then then click Import groups.
3. Make sure you get an error.
4. Now, try again, but set the Encoding to ISO-8859-6 and repeat the first step.
5. Make sure the group arabic1 is imported.

Test 4 - Invalid file

1. Return to the groups import page.
2. Try to import test4.csv, with the default CSV delimiter and Encoding.
3. Make sure you get the error:

   There is something wrong with the format of the CSV file. Please check the number of headings and columns match, and that the delimiter and file encoding are correct: Invalid CSV file format - number of columns is not constant!