Instructions to run tests from the command line

docs/TESTS.md

@@ -12,4 +12,49 @@ As you make changes to the solution you are writing use your editor's functional
 
 Remember to evaluate `(exercise-name-test:run-tests)` to re-run the tests after loading your updated solution.
 
+## Testing from the command line
 
+Executing the tests from the command line is possible, but it depends on which CL implementation you have chosen.
+For example, with SBCL you could execute this in the directory for exercise "foo"
+
+```sh
+sbcl --noinform \
+     --load foo-test \
+     --eval '(exit :code (if (foo-test:run-tests) 0 1))'
+```
+
+Other CL implementations will have similar but slightly different command-line options and exit commands.
+
+This assumes you have already installed SBCL and Quicklisp.
+See [Installing Common Lisp locally](https://exercism.org/docs/tracks/common-lisp/installation)
+
+~~~~exercism/note
+That command can be made more convenient. The `exercism` CLI has been updated so that the command
+
+```sh
+exercism test
+```
+
+does "The Right Thing"™ to invoke the test suite for _most tracks_.
+Unfortunately CL does not benefit because there is no single prescribed way to run the tests.
+
+However, there are ways to wrap the exercism CLI to provide additional functionality, or override existing functionality.
+If you use the bash shell, you can add the following to your `~/.bashrc` file.
+It looks complicated but it just checks that you are in a directory for a CL exercise and invokes SBCL:
+
+```sh
+function exercism {
+    if [[ $1 == "test" && $PWD =~ "$(command exercism workspace)/common-lisp/"([^/]+) ]]
+    then
+        local exercise=${BASH_REMATCH[1]}
+        sbcl --noinform \
+             --load "${exercise}-test" \
+             --eval "(exit :code (if (${exercise}-test:run-tests) 0 1))"
+    else
+        command exercism "$@"
+    fi
+}
+```
+
+With that, you can run `exercism test` to run the tests for your CL exercises.
+~~~~