test-terminal: set TERM=vt100

The point of the test-terminal script is to simulate in the
test scripts an environment where output is going to a real
terminal.

But since test-lib.sh also sets TERM=dumb, the simulation
isn't very realistic. The color code will skip auto-coloring
for TERM=dumb, leading to us liberally sprinkling

  test_terminal env TERM=vt100 git ...

through the test suite to convince the tests to actually
generate colors. Let's set TERM for programs run under
test_terminal, which is one less thing for test-writers to
remember.

In most cases the callers can be simplified, but note there
is one interesting case in t4202. It uses test_terminal to
check the auto-enabling of --decorate, but the expected
output _doesn't_ contain colors (because TERM=dumb
suppresses them). Using TERM=vt100 is closer to what the
real world looks like; adjust the expected output to match.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3203-branch-output.sh

@@ -253,7 +253,7 @@ test_expect_success '%(color) omitted without tty' '
 '
 
 test_expect_success TTY '%(color) present with tty' '
-	test_terminal env TERM=vt100 git branch $color_args >actual.raw &&
+	test_terminal git branch $color_args >actual.raw &&
 	test_decode_color <actual.raw >actual &&
 	test_cmp expect.color actual
 '

t/t4202-log.sh

@@ -750,7 +750,7 @@ test_expect_success 'log.decorate config parsing' '
 '
 
 test_expect_success TTY 'log output on a TTY' '
-	git log --oneline --decorate >expect.short &&
+	git log --color --oneline --decorate >expect.short &&
 
 	test_terminal git log --oneline >actual &&
 	test_cmp expect.short actual

t/t6006-rev-list-format.sh

@@ -229,8 +229,7 @@ do
 	'
 
 	test_expect_success TTY "$desc respects --color=auto (stdout is tty)" '
-		test_terminal env TERM=vt100 \
-			git log --format=$color -1 --color=auto >actual &&
+		test_terminal git log --format=$color -1 --color=auto >actual &&
 		has_color actual
 	'
 

t/t6300-for-each-ref.sh

@@ -425,8 +425,7 @@ test_expect_success 'set up color tests' '
 '
 
 test_expect_success TTY '%(color) shows color with a tty' '
-	test_terminal env TERM=vt100 \
-		git for-each-ref --format="$color_format" >actual.raw &&
+	test_terminal git for-each-ref --format="$color_format" >actual.raw &&
 	test_decode_color <actual.raw >actual &&
 	test_cmp expected.color actual
 '

t/t7004-tag.sh

@@ -1914,7 +1914,7 @@ test_expect_success '%(color) omitted without tty' '
 '
 
 test_expect_success TTY '%(color) present with tty' '
-	test_terminal env TERM=vt100 git tag $color_args >actual.raw &&
+	test_terminal git tag $color_args >actual.raw &&
 	test_decode_color <actual.raw >actual &&
 	test_cmp expect.color actual
 '

t/t7006-pager.sh

@@ -159,7 +159,7 @@ test_expect_success 'no color when stdout is a regular file' '
 test_expect_success TTY 'color when writing to a pager' '
 	rm -f paginated.out &&
 	test_config color.ui auto &&
-	test_terminal env TERM=vt100 git log &&
+	test_terminal git log &&
 	colorful paginated.out
 '
 
@@ -167,7 +167,7 @@ test_expect_success TTY 'colors are suppressed by color.pager' '
 	rm -f paginated.out &&
 	test_config color.ui auto &&
 	test_config color.pager false &&
-	test_terminal env TERM=vt100 git log &&
+	test_terminal git log &&
 	! colorful paginated.out
 '
 
@@ -186,7 +186,7 @@ test_expect_success 'color when writing to a file intended for a pager' '
 test_expect_success TTY 'colors are sent to pager for external commands' '
 	test_config alias.externallog "!git log" &&
 	test_config color.ui auto &&
-	test_terminal env TERM=vt100 git -p externallog &&
+	test_terminal git -p externallog &&
 	colorful paginated.out
 '
 

t/test-terminal.perl

@@ -80,6 +80,7 @@ sub copy_stdio {
 if ($#ARGV < 1) {
 	die "usage: test-terminal program args";
 }
+$ENV{TERM} = 'vt100';
 my $master_in = new IO::Pty;
 my $master_out = new IO::Pty;
 my $master_err = new IO::Pty;