Implement QB Writer Unit Tests

[robons]

• _get_default_value_uri_for_code_list_concepts - Ensure it generates appropriate default valueUrl for both dataset-local and global-level code lists.
• _get_default_property_value_uris_for_column - Ensure default propertyUrl and valueUrl values/templates are generated for {New/Existing}Qb{Dimension/Attribute}, QbMultiUnits, QbMultiMeasureDimension and QbObservationValue.
• _define_csvw_column_for_qb_column - Ensure column.output_uri_template overrides whatever defaultValueUrl is relevant for the component.
• _generate_csvqb_column - Ensure SuppressedCsvColumn gets suppressed. Ensure titles/name properties are set from CsvColumn input.

[robons]

Some thoughts on _get_default_value_uri_for_code_list_concepts

Cities,Value
Birmingham,20

QbColumn("Cities", ExistingQbDimension("http://gss-data.org.uk/def/dimension/cities"),
                   column_output_uri="http://gss-data.org.uk/def/concept-scheme/cities/{+cities}")

QbColumn("Cities", ExistingQbDimension("http://gss-data.org.uk/def/dimension/cities"))

codelist_uri = lookup(dimension_uri) # http://gss-data.org.uk/def/concept-scheme/cities

if codelist_uri looks like family/global codelist:
    http://gss-data.org.uk/def/concept-scheme/cities/{+cities}
elif codelist_uri looks like a dataset local one:
    http://gss-data.org.uk/data/some-dataset-name#concept/cities/{+cities}

What we want to test:

family/global: test that "http://gss-data.org.uk/def/concept-scheme/cities" gets converted to "http://gss-data.org.uk/def/concept-scheme/cities/{+cities}"

dataset-local: test that "http://gss-data.org.uk/data/some-dataset-name#scheme/cities" gets converted to "http://gss-data.org.uk/data/some-dataset-name#concept/cities/{+cities}"

anything which doesn't match the above two should get converted to just "{+cities}"

[robons]

Adding in a bit of work to this task:

• _generate_virtual_columns_for_obs_val - Test that a virt_unit column gets added where the user sets a single unit against a QbObservationValue column. Test the corresponding thing with the virt_measure column.