; test/README: Document TEST_LOAD_EL parameter.

test/README

@@ -44,6 +44,12 @@ If your test file contains the tests "test-foo", "test2-foo" and
 "test-foo-remote", and you want to run only the former two tests, you
 could use a selector regexp: "make <filename> SELECTOR='\"foo$$\"'".
 
+Note that although the test files are always compiled (unless they set
+no-byte-compile), the source files will be run by default, to give
+nicer backtraces.  To run the compiled version of a test use
+
+    make TEST_LOAD_EL=no ...
+
 
 (Also, see etc/compilation.txt for compilation mode font lock tests.)