Update tests.yml

Author: trusktr

.github/workflows/tests.yml

@@ -22,7 +22,8 @@ jobs:
       - name: npm install, build, and test
         # Note, we run bench and cov just to make sure they run successfully, but we're not doing anything with the result yet.
         run: |
-          if tty; then echo 'in a tty'; else echo 'NOT in a tty'; fi
+          isInteractive=$(tty -s && echo true || echo false)
+          if $isInteractive; then echo 'in a tty'; else echo 'NOT in a tty'; fi
           npm install
           npm run build
           npm run doc