t4015: test the output of "diff --color-moved -b"

Commit fa5ba2c1dd (diff: fix infinite loop with
--color-moved --ignore-space-change, 2017-10-12) added a
test to make sure that "--color-moved -b" doesn't run
forever, but the test in question doesn't actually have any
moved lines in it.

Let's scrap that test and add a variant of the existing
"--color-moved -w" test, but this time we'll check that we
find the move with whitespace changes, but not arbitrary
whitespace additions.

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

t/t4015-diff-whitespace.sh

@@ -1399,6 +1399,70 @@ test_expect_success 'move detection ignoring whitespace ' '
 	test_cmp expected actual
 '
 
+test_expect_success 'move detection ignoring whitespace changes' '
+	git reset --hard &&
+	# Lines 6-8 have a space change, but 9 is new whitespace
+	q_to_tab <<-\EOF >lines.txt &&
+	longQline 6
+	longQline 7
+	longQline 8
+	long liQne 9
+	line 1
+	line 2
+	line 3
+	line 4
+	line 5
+	EOF
+
+	git diff HEAD --no-renames --color-moved --color |
+		grep -v "index" |
+		test_decode_color >actual &&
+	cat <<-\EOF >expected &&
+	<BOLD>diff --git a/lines.txt b/lines.txt<RESET>
+	<BOLD>--- a/lines.txt<RESET>
+	<BOLD>+++ b/lines.txt<RESET>
+	<CYAN>@@ -1,9 +1,9 @@<RESET>
+	<GREEN>+<RESET><GREEN>long	line 6<RESET>
+	<GREEN>+<RESET><GREEN>long	line 7<RESET>
+	<GREEN>+<RESET><GREEN>long	line 8<RESET>
+	<GREEN>+<RESET><GREEN>long li	ne 9<RESET>
+	 line 1<RESET>
+	 line 2<RESET>
+	 line 3<RESET>
+	 line 4<RESET>
+	 line 5<RESET>
+	<RED>-long line 6<RESET>
+	<RED>-long line 7<RESET>
+	<RED>-long line 8<RESET>
+	<RED>-long line 9<RESET>
+	EOF
+	test_cmp expected actual &&
+
+	git diff HEAD --no-renames -b --color-moved --color |
+		grep -v "index" |
+		test_decode_color >actual &&
+	cat <<-\EOF >expected &&
+	<BOLD>diff --git a/lines.txt b/lines.txt<RESET>
+	<BOLD>--- a/lines.txt<RESET>
+	<BOLD>+++ b/lines.txt<RESET>
+	<CYAN>@@ -1,9 +1,9 @@<RESET>
+	<CYAN>+<RESET><CYAN>long	line 6<RESET>
+	<CYAN>+<RESET><CYAN>long	line 7<RESET>
+	<CYAN>+<RESET><CYAN>long	line 8<RESET>
+	<GREEN>+<RESET><GREEN>long li	ne 9<RESET>
+	 line 1<RESET>
+	 line 2<RESET>
+	 line 3<RESET>
+	 line 4<RESET>
+	 line 5<RESET>
+	<MAGENTA>-long line 6<RESET>
+	<MAGENTA>-long line 7<RESET>
+	<MAGENTA>-long line 8<RESET>
+	<RED>-long line 9<RESET>
+	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
@@ -1549,13 +1613,4 @@ test_expect_success 'move detection with submodules' '
 	test_cmp expect decoded_actual
 '
 
-test_expect_success 'move detection with whitespace changes' '
-	test_when_finished "git reset --hard" &&
-	test_seq 10 >test &&
-	git add test &&
-	sed s/3/42/ <test >test.tmp &&
-	mv test.tmp test &&
-	git -c diff.colormoved diff --ignore-space-change -- test
-'
-
 test_done