Open the model. Specify coverage settings and turn on coverage recording.

modelName = 'sldemo_lct_bus';
open_system(modelName);
set_param(modelName,'CovMetricSettings','dcme','RecordCoverage','on');

Create a BlockSelector object, bl. This block selector selects all blocks in the model with the property 'RelationalOperator'.

bl = slcoverage.BlockSelector(slcoverage.BlockSelectorType.BlockType,'RelationalOperator');

Create a filter object, create a rule object, and add the rule to the filter object.

filt = slcoverage.Filter;
rule = slcoverage.FilterRule(bl,'Tested elsewhere',slcoverage.FilterMode.Exclude);
filt.addRule(rule);