[PATCH 2/2] Perl coverage support using Devel::Cover.

[Ralf Wildenhues]

With this, you can run
  make -k check-coverage

and on the next day, you might have useful coverage data.  :-)

Well, if something failed, you might still need to follow up with
  make check-coverage-report

Pausing for some coffee is still worthwhile at this point.
For a reasonably sane edit-compile-cycle, use
  make -k recheck-coverage

or limit the set of tests to be run
  make -k check-coverage TESTS="foo.test bar.test"
  make check-coverage-report


The environment variable WANT_NO_THREADS is used to skip those tests
that required ithreads.

I thought of hooking clean-coverage to maintainer-clean-local, but that
doesn't help much, as Devel::Cover invalidates coverage data for changed
scripts as well.

Cheers,
Ralf

    Perl coverage support using Devel::Cover.
    
    This introduces makefile rules to run the testsuite with Perl
    coverage enabled.  It skips tests that use perl ithreads, by
    unsetting AUTOMAKE_JOBS and setting WANT_NO_THREADS to make the
    threaded tests skip.
    
    * Makefile.am (PERL_COVERAGE_DB, PERL_COVERAGE_FLAGS)
    (PERL_COVER): New variables.
    (check-coverage, recheck-coverage, clean-coverage): New phony
    targets.
    (check-coverage-run, recheck-coverage-run): New phony helper
    targets.
    (clean-local): New, depend on clean-coverage.
    * lib/Automake/tests/Condition-t.pl: Skip if WANT_NO_THREADS is
    set.
    * lib/Automake/tests/DisjConditions-t.pl: Likewise.
    * tests/defs.in: New required entry 'perl-threads'.
    * tests/parallel-am.test: Use it to skip if WANT_NO_THREADS is
    set.
    * tests/parallel-am2.test: Likewise.
    * tests/parallel-am3.test: Likewise.

diff --git a/HACKING b/HACKING
index 64d55f9..c8ae47e 100644
--- a/HACKING
+++ b/HACKING
@@ -125,6 +125,9 @@
 * Use `keep_testdirs=yes' to keep test directories for successful
   tests also.
 
+* Use perl coverage information to ensure your new code is thoroughly
+  tested by your new tests.
+
 ================================================================
 = Release procedure
 
diff --git a/Makefile.am b/Makefile.am
index 66d8315..fc16b7a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -121,6 +121,41 @@ recheck:
 dist-hook:
        cd $(distdir)/tests && chmod a+rx *.test
 
+
+# Perl coverage statistics.
+PERL_COVERAGE_DB = $(abs_top_builddir)/cover_db
+PERL_COVERAGE_FLAGS = 
-MDevel::Cover=-db,$(PERL_COVERAGE_DB),-silent,on,-summary,off
+PERL_COVER = cover
+
+check-coverage-run recheck-coverage-run: all
+       $(mkinstalldirs) $(PERL_COVERAGE_DB)
+       PERL5OPT="$$PERL5OPT $(PERL_COVERAGE_FLAGS)"; export PERL5OPT; \
+       WANT_NO_THREADS=yes; export WANT_NO_THREADS; unset AUTOMAKE_JOBS; \
+       $(MAKE) $(AM_MAKEFLAGS) `echo $@ | sed 's/-coverage-run//'`
+
+check-coverage-report:
+       @if test ! -d "$(PERL_COVERAGE_DB)"; then \
+         echo "No coverage database found in \`$(PERL_COVERAGE_DB)'." >&2; \
+         echo "Please run \`make check-coverage' first" >&2; \
+         exit 1; \
+       fi
+       $(PERL_COVER) $(PERL_COVER_FLAGS) "$(PERL_COVERAGE_DB)"
+
+# We don't use direct dependencies here because we'd like to be able
+# to invoke the report even after interrupted check-coverage.
+check-coverage: check-coverage-run
+       $(MAKE) $(AM_MAKEFLAGS) check-coverage-report
+
+recheck-coverage: recheck-coverage-run
+       $(MAKE) $(AM_MAKEFLAGS) check-coverage-report
+
+clean-coverage:
+       rm -rf "$(PERL_COVERAGE_DB)"
+clean-local: clean-coverage
+
+.PHONY: check-coverage recheck-coverage check-coverage-run \
+       recheck-coverage-run check-coverage-report clean-coverage
+
 # Some simple checks, and then ordinary check.  These are only really
 # guaranteed to work on my machine.
 syntax_check_rules = \
diff --git a/lib/Automake/tests/Condition-t.pl 
b/lib/Automake/tests/Condition-t.pl
index 06eb34e..0f1dde8 100644
--- a/lib/Automake/tests/Condition-t.pl
+++ b/lib/Automake/tests/Condition-t.pl
@@ -1,4 +1,5 @@
-# Copyright (C) 2001, 2002, 2003, 2008  Free Software Foundation, Inc.
+# Copyright (C) 2001, 2002, 2003, 2008, 2009  Free Software Foundation,
+# Inc.
 #
 # This file is part of GNU Automake.
 #
@@ -18,7 +19,8 @@
 BEGIN {
   use Config;
   if (eval { require 5.007_002; }      # for CLONE support
-      && $Config{useithreads})
+      && $Config{useithreads}
+      && !$ENV{WANT_NO_THREADS})
     {
       require threads;
       import threads;
diff --git a/lib/Automake/tests/DisjConditions-t.pl 
b/lib/Automake/tests/DisjConditions-t.pl
index 2fe275b..eccdcd6 100644
--- a/lib/Automake/tests/DisjConditions-t.pl
+++ b/lib/Automake/tests/DisjConditions-t.pl
@@ -1,4 +1,5 @@
-# Copyright (C) 2001, 2002, 2003, 2008  Free Software Foundation, Inc.
+# Copyright (C) 2001, 2002, 2003, 2008, 2009  Free Software Foundation,
+# Inc.
 #
 # This file is part of GNU Automake.
 #
@@ -18,7 +19,8 @@
 BEGIN {
   use Config;
   if (eval { require 5.007_002; }      # for CLONE support
-      && $Config{useithreads})
+      && $Config{useithreads}
+      && !$ENV{WANT_NO_THREADS})
     {
       require threads;
       import threads;
diff --git a/tests/defs.in b/tests/defs.in
index ecdf069..6eec344 100644
--- a/tests/defs.in
+++ b/tests/defs.in
@@ -170,6 +170,10 @@ do
       rm -f $priv_check_temp
       test $overwrite_status = 0 && exit 77
       ;;
+    perl-threads)
+      # Skip with Devel::Cover: it cannot cope with threads.
+      test "$WANT_NO_THREADS" = yes && exit 77
+      ;;
     python)
       # Python doesn't support --version, it has -V
       echo "$me: running python -V"
diff --git a/tests/parallel-am.test b/tests/parallel-am.test
index 4aef628..c46377b 100755
--- a/tests/parallel-am.test
+++ b/tests/parallel-am.test
@@ -1,5 +1,5 @@
 #! /bin/sh
-# Copyright (C) 2008  Free Software Foundation, Inc.
+# Copyright (C) 2008, 2009  Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -35,6 +35,7 @@
 #
 # This test checks (0), (1), and (2).  See sister tests for further coverage.
 
+required=perl-threads
 . ./defs || Exit 1
 
 set -e
diff --git a/tests/parallel-am2.test b/tests/parallel-am2.test
index 20225a0..d929740 100755
--- a/tests/parallel-am2.test
+++ b/tests/parallel-am2.test
@@ -1,5 +1,5 @@
 #! /bin/sh
-# Copyright (C) 2008  Free Software Foundation, Inc.
+# Copyright (C) 2008, 2009  Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -20,6 +20,7 @@
 # 4) warning and normal error output should be identical, in that duplicate
 #    warnings should be omitted in the same way as without threads,
 
+required=perl-threads
 . ./defs || Exit 1
 
 set -e
diff --git a/tests/parallel-am3.test b/tests/parallel-am3.test
index 5db9c67..104376a 100755
--- a/tests/parallel-am3.test
+++ b/tests/parallel-am3.test
@@ -1,5 +1,5 @@
 #! /bin/sh
-# Copyright (C) 2008  Free Software Foundation, Inc.
+# Copyright (C) 2008, 2009  Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -21,6 +21,7 @@
 #    with --add-missing, even with concurrent file requirements, and the
 #    installation of aux files should be race-free,
 
+required=perl-threads
 . ./defs || Exit 1
 
 set -e