Fix 1611 incorrect errors when validating data with a missiing required column

[amelie-rondot]

• fixes Incorrect errors when validating data with a missing required column #1611

---

This PR fixes incorrect errors which occur when validating data with missing required column, for the specific case of schema_syncoption.

After investigating, the better way to fix these incorrect errors we found is to remove missing columns from field_info Row.__init__() parameter at the creation of the Row in row_stream() local method.

Test cases have been added to traduce expected behavior:
Validation of tabular data with schema with one or many required fields, and data with one or many missing required columns and schema_sync option is set to true

Other test cases have not been broken.

Expected behavior could also be observed with command line:

frictionless run validate data.csv --schema schema.json --schema-sync

with:

schema.json
----
{
    "$schema": "https://frictionlessdata.io/schemas/table-schema.json",
    "fields": [
        {
            "name": "A",
            "title": "Field A",
            "type": "string",
            "constraints": {"required": true}
        },
        {"name": "B", "title": "Field B", "type": "string"},
        {"name": "C", "title": "Field C", "type": "string"}
    ]
}

data.csv
----
B, C
b, c

Only one error missing-label in the header's field "A" occurs in the validation report, as expected.

[roll]

Thanks @amelie-rondot !

Can you please make format?

[amelie-rondot]

@roll thanks a lot for reviewing!
I committed format fixes.

[roll]

Thanks!

I added a comment

[roll]

Is it possible to move it from the row iteration cycle? Currently, this code will be executed for every row in a table

[amelie-rondot]

Thanks!
Indeed, you're right, it's possible to move this block before initializing row_stream TableResource attribute.
I've just committed it. I also added some new test cases to insure that resulting behaviour corresponds to the expected one.

[roll]

Thanks a lot!