Describe Makefile test targets in test/README

* CONTRIBUTE: Move Makefile test targets to test/README.

* Makefile.in:
* test/README: Describe Makefile test targets.

CONTRIBUTE

@@ -257,26 +257,8 @@ If your test lasts longer than some few seconds, mark it in its
 To run tests on the entire Emacs tree, run "make check" from the
 top-level directory.  Most tests are in the directory
 "test/automated".  From the "test/automated" directory, run "make
-<filename>" to run the tests for <filename>.el(c).  See
+<filename>" to run the tests for <filename>.el(c).  See "test/README"
-"test/automated/Makefile" for more information.
+for more information.
-
-Tests which are tagged ":expensive-test" are enabled additionally, if
-you run "make check-expensive" from the top-level directory.  "make
-<filename>" as mentioned above incorporates expensive tests for
-<filename>.el(c). You can also define any ert selector on the command
-line. So "make check SELECTOR=nil" is equivalent to "make
-check-expensive".
-
-You could also use predefined selectors of the Makefile. "make
-<filename> SELECTOR='$(SELECTOR_DEFAULT)'" runs all tests for
-<filename>.el(c) except the tests tagged as expensive.
-
-Selectors can be defined with different methods, see (info "(ert)Test
-Selectors") or
-https://www.gnu.org/software/emacs/manual/html_node/ert/Test-Selectors.html
-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 regexp: "make <filename> SELECTOR='\"foo$$\"'" .
 
 ** Understanding Emacs Internals.
 

Makefile.in

@@ -57,6 +57,10 @@
 #
 # make docs
 #      Make Emacs documentation files from their sources; requires makeinfo.
+#
+# make check  or  make check-expensive
+#      Run Emacs test suite.  check-expensive runs also tests which
+#      take more time to perform.
 
 SHELL = @SHELL@
 

test/README

@@ -1,4 +1,62 @@
+Copyright (C) 2008-2016 Free Software Foundation, Inc.
+See the end of the file for license conditions.
+
 This directory contains files intended to test various aspects of
 Emacs's functionality.  Please help add tests!
 
+Emacs uses ERT, Emacs Lisp Regression Testing, for testing.  See (info
+"(ert)") or https://www.gnu.org/software/emacs/manual/html_node/ert/
+for more information on writing and running tests.
+
+All ERT test files are supposed to run from subdirectory automated/.
+The Makefile in that directory supports the following targets:
+
+* make check
+  Run all tests as defined in the directory.  Expensive tests are
+  suppressed.  The result of the tests for <filename>.el is stored in
+  <filename>.log.
+
+* make check-maybe
+  Like "make check", but run only the tests for files which have
+  unresolved prerequisites.
+
+* make check-expensive
+  Like "make check", but run also the tests marked as expensive.
+
+* make <filename>  or  make <filename>.log
+  Run all tests declared in <filename>.el.  This includes expensive
+  tests.  In the former case the output is shown on the terminal, in
+  the latter case the output is written to <filename>.log.
+
+ERT offers selectors, which make it possible to filter out which test
+cases shall run.  The make variable $(SELECTOR) gives you a simple
+mean to use your own selectors.  The ERT manual describes how
+selectors are constructed, see (info "(ert)Test Selectors") or
+https://www.gnu.org/software/emacs/manual/html_node/ert/Test-Selectors.html
+
+You could use predefined selectors of the Makefile.  "make <filename>
+SELECTOR='$(SELECTOR_DEFAULT)'" runs all tests for <filename>.el
+except the tests tagged as expensive.
+
+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$$\"'".
+
+
 (Also, see etc/compilation.txt for compilation mode font lock tests.)
+
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.