diff --git a/scripts/coverage.sh b/scripts/coverage.sh
index 5c07b211f..0412fcd1a 100755
--- a/scripts/coverage.sh
+++ b/scripts/coverage.sh
@@ -29,7 +29,7 @@ fi
 rm -rf target/cov/$reportName
 
 _ cargo +nightly build --target-dir target/cov --all
-_ cargo +nightly test --target-dir target/cov --lib --all
+_ cargo +nightly test --target-dir target/cov --lib --all -- --test-threads=1
 
 _ scripts/fetch-grcov.sh
 echo "--- grcov"