update test coverage script

tests/check_coverage

@@ -1,22 +1,15 @@
 #!/bin/bash
+# Run all tests and check coverage
 
 export SCIRIS_BACKEND='agg' # Don't open up figures
 
-# To use pytest-xdist (more robust), use -n auto; to use pytest-parallel (faster), use --workers=auto
-method=${1:-robust}
-if [ $method == "fast" ]; then
-    parallel='--workers=auto'
-else
-    parallel=' -n auto'
-fi
-
 echo 'Running tests...'
-pytest -v test_*.py --cov-config=.coveragerc --cov=../sciris --durations=0 $parallel
+pytest -v test_*.py -n auto --cov-config=.coveragerc --cov=../sciris --durations=0
 
 echo 'Creating HTML report...'
 coverage html
 
-echo 'Running report...'
+echo 'Printing report...'
 coverage report
 
 echo 'Report location:'