diff-highlight: add some tests

Signed-off-by: Brian Henderson <henderson.bj@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/diff-highlight/Makefile

@@ -0,0 +1,5 @@
+# nothing to build
+all:
+
+test:
+	$(MAKE) -C t

contrib/diff-highlight/t/Makefile

@@ -0,0 +1,22 @@
+-include ../../../config.mak.autogen
+-include ../../../config.mak
+
+# copied from ../../t/Makefile
+SHELL_PATH ?= $(SHELL)
+SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
+T = $(wildcard t[0-9][0-9][0-9][0-9]-*.sh)
+
+all: test
+test: $(T)
+
+.PHONY: help clean all test $(T)
+
+help:
+	@echo 'Run "$(MAKE) test" to launch test scripts'
+	@echo 'Run "$(MAKE) clean" to remove trash folders'
+
+$(T):
+	@echo "*** $@ ***"; '$(SHELL_PATH_SQ)' $@ $(GIT_TEST_OPTS)
+
+clean:
+	$(RM) -r 'trash directory'.*

contrib/diff-highlight/t/t9400-diff-highlight.sh

@@ -0,0 +1,163 @@
+#!/bin/sh
+
+test_description='Test diff-highlight'
+
+CURR_DIR=$(pwd)
+TEST_OUTPUT_DIRECTORY=$(pwd)
+TEST_DIRECTORY="$CURR_DIR"/../../../t
+DIFF_HIGHLIGHT="$CURR_DIR"/../diff-highlight
+
+CW="$(printf "\033[7m")"	# white
+CR="$(printf "\033[27m")"	# reset
+
+. "$TEST_DIRECTORY"/test-lib.sh
+
+if ! test_have_prereq PERL
+then
+	skip_all='skipping diff-highlight tests; perl not available'
+	test_done
+fi
+
+# dh_test is a test helper function which takes 3 file names as parameters. The
+# first 2 files are used to generate diff and commit output, which is then
+# piped through diff-highlight. The 3rd file should contain the expected output
+# of diff-highlight (minus the diff/commit header, ie. everything after and
+# including the first @@ line).
+dh_test () {
+	a="$1" b="$2" &&
+
+	cat >patch.exp &&
+
+	{
+		cat "$a" >file &&
+		git add file &&
+		git commit -m "Add a file" &&
+
+		cat "$b" >file &&
+		git diff file >diff.raw &&
+		git commit -a -m "Update a file" &&
+		git show >commit.raw
+	} >/dev/null &&
+
+	"$DIFF_HIGHLIGHT" <diff.raw | test_strip_patch_header >diff.act &&
+	"$DIFF_HIGHLIGHT" <commit.raw | test_strip_patch_header >commit.act &&
+	test_cmp patch.exp diff.act &&
+	test_cmp patch.exp commit.act
+}
+
+test_strip_patch_header () {
+	sed -n '/^@@/,$p' $*
+}
+
+test_expect_success 'diff-highlight highlights the beginning of a line' '
+	cat >a <<-\EOF &&
+		aaa
+		bbb
+		ccc
+	EOF
+
+	cat >b <<-\EOF &&
+		aaa
+		0bb
+		ccc
+	EOF
+
+	dh_test a b <<-EOF
+		@@ -1,3 +1,3 @@
+		 aaa
+		-${CW}b${CR}bb
+		+${CW}0${CR}bb
+		 ccc
+	EOF
+'
+
+test_expect_success 'diff-highlight highlights the end of a line' '
+	cat >a <<-\EOF &&
+		aaa
+		bbb
+		ccc
+	EOF
+
+	cat >b <<-\EOF &&
+		aaa
+		bb0
+		ccc
+	EOF
+
+	dh_test a b <<-EOF
+		@@ -1,3 +1,3 @@
+		 aaa
+		-bb${CW}b${CR}
+		+bb${CW}0${CR}
+		 ccc
+	EOF
+'
+
+test_expect_success 'diff-highlight highlights the middle of a line' '
+	cat >a <<-\EOF &&
+		aaa
+		bbb
+		ccc
+	EOF
+
+	cat >b <<-\EOF &&
+		aaa
+		b0b
+		ccc
+	EOF
+
+	dh_test a b <<-EOF
+		@@ -1,3 +1,3 @@
+		 aaa
+		-b${CW}b${CR}b
+		+b${CW}0${CR}b
+		 ccc
+	EOF
+'
+
+test_expect_success 'diff-highlight does not highlight whole line' '
+	cat >a <<-\EOF &&
+		aaa
+		bbb
+		ccc
+	EOF
+
+	cat >b <<-\EOF &&
+		aaa
+		000
+		ccc
+	EOF
+
+	dh_test a b <<-EOF
+		@@ -1,3 +1,3 @@
+		 aaa
+		-bbb
+		+000
+		 ccc
+	EOF
+'
+
+test_expect_failure 'diff-highlight highlights mismatched hunk size' '
+	cat >a <<-\EOF &&
+		aaa
+		bbb
+	EOF
+
+	cat >b <<-\EOF &&
+		aaa
+		b0b
+		ccc
+	EOF
+
+	dh_test a b <<-EOF
+		@@ -1,3 +1,3 @@
+		 aaa
+		-b${CW}b${CR}b
+		+b${CW}0${CR}b
+		+ccc
+	EOF
+'
+
+# TODO add multi-byte test
+
+test_done