t4015: refactor --color-moved whitespace test

In preparation for testing several different whitespace
options, let's split out the setup and cleanup steps of the
whitespace test.

While we're here, let's also switch to using "<<-" to indent
our here-documents properly, and use q_to_tab to more
explicitly mark where we expect whitespace to appear.

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

t/t4015-diff-whitespace.sh

@@ -1318,30 +1318,34 @@ test_expect_success 'no effect from --color-moved with --word-diff' '
 	test_cmp expect actual
 '
 
-test_expect_success 'move detection ignoring whitespace ' '
+test_expect_success 'set up whitespace tests' '
 	git reset --hard &&
-	cat <<\EOF >lines.txt &&
-line 1
-line 2
-line 3
-line 4
-long line 5
-long line 6
-long line 7
-EOF
-	git add lines.txt &&
-	git commit -m "add poetry" &&
-	cat <<\EOF >lines.txt &&
+	# Note that these lines have no leading or trailing whitespace.
+	cat <<-\EOF >lines.txt &&
+	line 1
+	line 2
+	line 3
+	line 4
 	long line 5
 	long line 6
 	long line 7
-line 1
-line 2
-line 3
-line 4
-EOF
-	test_config color.diff.oldMoved "magenta" &&
-	test_config color.diff.newMoved "cyan" &&
+	EOF
+	git add lines.txt &&
+	git commit -m "add poetry" &&
+	git config color.diff.oldMoved "magenta" &&
+	git config color.diff.newMoved "cyan"
+'
+
+test_expect_success 'move detection ignoring whitespace ' '
+	q_to_tab <<-\EOF >lines.txt &&
+	Qlong line 5
+	Qlong line 6
+	Qlong line 7
+	line 1
+	line 2
+	line 3
+	line 4
+	EOF
 	git diff HEAD --no-renames --color-moved --color |
 		grep -v "index" |
 		test_decode_color >actual &&
@@ -1385,6 +1389,11 @@ EOF
 	test_cmp expected actual
 '
 
+test_expect_success 'clean up whitespace-test colors' '
+	git config --unset color.diff.oldMoved &&
+	git config --unset color.diff.newMoved
+'
+
 test_expect_success '--color-moved block at end of diff output respects MIN_ALNUM_COUNT' '
 	git reset --hard &&
 	>bar &&