[PATCH v4 7/7] t7006-pager: if stdout is not a terminal, make a new one

From

Jonathan Nieder <jrnieder@gmail.com>

Date

Feb 21, 2010, 02:09 UTC

Message-ID

<20100221020922.GB7651@progeny.tock>

In-Reply-To

<20100221020317.GA7651@progeny.tock>

 - Replace all isatty calls with calls to a custom xisatty wrapper
   that usually checks for a terminal but can be overridden for tests.
   This would be workable, but it would require implementing xisatty
   separately in three languages (C, shell, and perl) and making sure
   that any code that is to be tested always uses the wrapper.

 - Redirect stdout to /dev/tty.  This would be problematic because
   there might be no terminal available, and even if a terminal is
   available, it might not be appropriate to spew output to it.

 - Create a new pseudo-terminal on the fly and capture its output.

This patch implements the third approach.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
Here’s test-terminal on top of that.  As long as this using IO::Pty
from CPAN, there’s not much reason not to use the often-used
IPC::Open3 to simplify this.

Thanks for bearing with me.

 t/t7006-pager.sh           |   35 ++++++++++++++++++++++++-----------
 t/t7006/test-terminal.perl |   28 ++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 11 deletions(-)
 create mode 100755 t/t7006/test-terminal.perl

diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 4f52ea5..da0f962 100644
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -5,18 +5,31 @@ test_description='Test automatic use of a pager.'
 . ./test-lib.sh
 
 rm -f stdout_is_tty
-test_expect_success 'is stdout a terminal?' '
+test_expect_success 'set up terminal for tests' '
 	if test -t 1
 	then
 		: > stdout_is_tty
+	elif
+		test_have_prereq PERL &&
+		"$PERL_PATH" "$TEST_DIRECTORY"/t7006/test-terminal.perl \
+			sh -c "test -t 1"
+	then
+		: > test_terminal_works
 	fi
 '
 
 if test -e stdout_is_tty
 then
+	test_terminal() { "$@"; }
+	test_set_prereq TTY
+elif test -e test_terminal_works
+then
+	test_terminal() {
+		"$PERL_PATH" "$TEST_DIRECTORY"/t7006/test-terminal.perl "$@"
+	}
 	test_set_prereq TTY
 else
-	say stdout is not a terminal, so skipping some tests.
+	say no usable terminal, so skipping some tests
 fi
 
 unset GIT_PAGER GIT_PAGER_IN_USE
@@ -30,13 +43,13 @@ test_expect_success 'setup' '
 
 rm -f paginated.out
 test_expect_success TTY 'some commands use a pager' '
-	git log &&
+	test_terminal git log &&
 	test -e paginated.out
 '
 
 rm -f paginated.out
 test_expect_success TTY 'some commands do not use a pager' '
-	git rev-list HEAD &&
+	test_terminal git rev-list HEAD &&
 	! test -e paginated.out
 '
 
@@ -54,7 +67,7 @@ test_expect_success 'no pager when stdout is a regular file' '
 
 rm -f paginated.out
 test_expect_success TTY 'git --paginate rev-list uses a pager' '
-	git --paginate rev-list HEAD  &&
+	test_terminal git --paginate rev-list HEAD &&
 	test -e paginated.out
 '
 
@@ -66,7 +79,7 @@ test_expect_success 'no pager even with --paginate when stdout is a pipe' '
 
 rm -f paginated.out
 test_expect_success TTY 'no pager with --no-pager' '
-	git --no-pager log &&
+	test_terminal git --no-pager log &&
 	! test -e paginated.out
 '
 
@@ -95,7 +108,7 @@ test_expect_success 'no color when stdout is a regular file' '
 rm -f paginated.out
 git config color.ui auto
 test_expect_success TTY 'color when writing to a pager' '
-	TERM=vt100 git log &&
+	TERM=vt100 test_terminal git log &&
 	colorful paginated.out
 '
 
@@ -127,7 +140,7 @@ test_expect_success SIMPLEPAGER 'default pager is used by default' '
 	: > default_pager_used
 	EOF
 	chmod +x $less &&
-	PATH=.:$PATH git log &&
+	PATH=.:$PATH test_terminal git log &&
 	test -e default_pager_used
 '
 
@@ -137,7 +150,7 @@ rm -f PAGER_used
 test_expect_success TTY 'PAGER overrides default pager' '
 	PAGER=": > PAGER_used" &&
 	export PAGER &&
-	git log &&
+	test_terminal git log &&
 	test -e PAGER_used
 '
 
@@ -147,7 +160,7 @@ test_expect_success TTY 'core.pager overrides PAGER' '
 	PAGER=: &&
 	export PAGER &&
 	git config core.pager ": > core.pager_used" &&
-	git log &&
+	test_terminal git log &&
 	test -e core.pager_used
 '
 
@@ -156,7 +169,7 @@ test_expect_success TTY 'GIT_PAGER overrides core.pager' '
 	git config core.pager : &&
 	GIT_PAGER=": > GIT_PAGER_used" &&
 	export GIT_PAGER &&
-	git log &&
+	test_terminal git log &&
 	test -e GIT_PAGER_used
 '
 
diff --git a/t/t7006/test-terminal.perl b/t/t7006/test-terminal.perl
new file mode 100755
index 0000000..fc3fbb4
--- /dev/null
+++ b/t/t7006/test-terminal.perl
@@ -0,0 +1,28 @@
+#!/usr/bin/perl
+use strict;
+use warnings;
+use IO::Pty;
+use File::Copy;
+use IPC::Open3;
+
+# Wait for $_[0] to finish.
+sub finish_child {
+	# Simplified from wait_or_whine() in run-command.c.
+	waitpid($_[0], 0) == $_[0] or die "waitpid failed: $!";
+	if ($? & 127) {
+		my $code = $? & 127;
+		warn "died of signal $code";
+		return $code - 128;
+	}
+	return $? >> 8;
+}
+
+@ARGV >= 1 or die "usage: test-terminal program args";
+my $master = new IO::Pty;
+my $slave = $master->slave;
+my $pid = open3(\*STDIN, '>&' . fileno($slave), \*STDERR, @ARGV);
+close $slave;
+# Reads from a disconnected terminal may return EIO or end-of-file.
+# Either is fine.
+copy($master, \*STDOUT, 4096) or $!{EIO} or die "cannot copy from child: $!";
+exit(finish_child($pid));

-- 
1.7.0