Print top time consuming tests if advised

* lisp/emacs-lisp/ert.el (ert-summarize-tests-batch-and-exit):
New argument HIGH.  Print top-running tests.

* test/Makefile.in (check-doit): Use ${SUMMARIZE_TESTS}.

* test/README: Explain SUMMARIZE_TESTS.

2 files changed, 7 insertions, 1 deletions

diff --git a/test/Makefile.in b/test/Makefile.in
index 20e90c6ce50..bf1f9f39b71 100644
--- a/test/Makefile.in
+++ b/test/Makefile.in
@@ -277,7 +277,8 @@ check-maybe: check-no-automated-subdir
 ## summarizing step from running when there is an error.
 check-doit:
         -@${MAKE} -k  ${LOGFILES}
-        @$(emacs) -l ert -f ert-summarize-tests-batch-and-exit ${LOGFILES}
+        @$(emacs) -l ert --eval \
+        "(ert-summarize-tests-batch-and-exit ${SUMMARIZE_TESTS})" ${LOGFILES}
 
 .PHONY: mostlyclean clean bootstrap-clean distclean maintainer-clean
 
diff --git a/test/README b/test/README
index 36307e3b6c1..b9f6f65c450 100644
--- a/test/README
+++ b/test/README
@@ -65,6 +65,11 @@ compiled version of a test use
 
     make TEST_LOAD_EL=no ...
 
+Some tests might take long time to run.  In order to summarize the
+<nn> tests with the longest duration, call
+
+    make SUMMARIZE_TESTS=<nn> ...
+
 
 (Also, see etc/compilation.txt for compilation mode font lock tests.)