diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
index d2aec0f38b..86286f263d 100755
--- a/t/t3203-branch-output.sh
+++ b/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
 '
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 3f3531f0a4..62f9d94fa3 100755
--- a/t/t4202-log.sh
+++ b/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
diff --git a/t/t6006-rev-list-format.sh b/t/t6006-rev-list-format.sh
index b326d550f3..98be78b4a2 100755
--- a/t/t6006-rev-list-format.sh
+++ b/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
 	'
 
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index 2274a4b733..d6bffe6273 100755
--- a/t/t6300-for-each-ref.sh
+++ b/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
 '
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index dd5ba450ee..6dc44478f9 100755
--- a/t/t7004-tag.sh
+++ b/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
 '
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 20b4d83c28..20caa3f095 100755
--- a/t/t7006-pager.sh
+++ b/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
 '
 
diff --git a/t/test-terminal.perl b/t/test-terminal.perl
index 96b6a03e1c..46bf618479 100755
--- a/t/test-terminal.perl
+++ b/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;