core.whitespace: add test for diff whitespace error highlighting

This tests seletive enabling/disabling of whitespace error
highlighting done by colored diff output.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t4019-diff-wserror.sh b/t/t4019-diff-wserror.sh
new file mode 100755 (executable)
index 0000000..dbc895b
--- /dev/null
+++ b/t/t4019-diff-wserror.sh
@@ -0,0 +1,76 @@
+#!/bin/sh
+
+test_description='diff whitespace error detection'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+
+       git config diff.color.whitespace "blue reverse" &&
+       >F &&
+       git add F &&
+       echo "         Eight SP indent" >>F &&
+       echo "  HT and SP indent" >>F &&
+       echo "With trailing SP " >>F &&
+       echo "No problem" >>F
+
+'
+
+blue_grep='7;34m' ;# ESC [ 7 ; 3 4 m
+
+test_expect_success default '
+
+       git diff --color >output
+       grep "$blue_grep" output >error
+       grep -v "$blue_grep" output >normal
+
+       grep Eight normal >/dev/null &&
+       grep HT error >/dev/null &&
+       grep With error >/dev/null &&
+       grep No normal >/dev/null
+
+'
+
+test_expect_success 'without -trail' '
+
+       git config core.whitespace -trail
+       git diff --color >output
+       grep "$blue_grep" output >error
+       grep -v "$blue_grep" output >normal
+
+       grep Eight normal >/dev/null &&
+       grep HT error >/dev/null &&
+       grep With normal >/dev/null &&
+       grep No normal >/dev/null
+
+'
+
+test_expect_success 'without -space' '
+
+       git config core.whitespace -space
+       git diff --color >output
+       grep "$blue_grep" output >error
+       grep -v "$blue_grep" output >normal
+
+       grep Eight normal >/dev/null &&
+       grep HT normal >/dev/null &&
+       grep With error >/dev/null &&
+       grep No normal >/dev/null
+
+'
+
+test_expect_success 'with indent-non-tab only' '
+
+       git config core.whitespace indent,-trailing,-space
+       git diff --color >output
+       grep "$blue_grep" output >error
+       grep -v "$blue_grep" output >normal
+
+       grep Eight error >/dev/null &&
+       grep HT normal >/dev/null &&
+       grep With normal >/dev/null &&
+       grep No normal >/dev/null
+
+'
+
+test_done