tracks/idris/docs/TESTS.md in trackler-2.2.1.19 vs tracks/idris/docs/TESTS.md in trackler-2.2.1.20

@@ -1,6 +1,13 @@
\ No newline at end of file
+To run tests from the command line:
+
+```bash
+idris --testpkg HelloWorld.ipkg
+```
+
+(Replace `HelloWorld.ipkg` with the `.ipkg` file in the root directory of each exercise.)