[PATCH v2 1/3] diff-highlight: add some tests.

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

@@ -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'.*

@@ -0,0 +1,62 @@
+#!/bin/sh
+
+test_description='Test diff-highlight'
+
+. ./test-diff-highlight.sh
+. "$TEST_DIRECTORY"/test-lib.sh
+
+# PERL is required, but assumed to be present, although not necessarily modern
+# some tests require 5.8
+test_expect_success PERL 'name' 'true'
+
+test_expect_success 'diff-highlight highlights the beginning of a line' '
+	dh_test \
+		"aaa\nbbb\nccc\n" \
+		"aaa\n0bb\nccc\n" \
+"
+ aaa
+-${CW}b${CR}bb
++${CW}0${CR}bb
+ ccc
+"
+'
+
+test_expect_success 'diff-highlight highlights the end of a line' '
+	dh_test \
+		"aaa\nbbb\nccc\n" \
+		"aaa\nbb0\nccc\n" \
+"
+ aaa
+-bb${CW}b${CR}
++bb${CW}0${CR}
+ ccc
+"
+'
+
+test_expect_success 'diff-highlight highlights the middle of a line' '
+	dh_test \
+		"aaa\nbbb\nccc\n" \
+		"aaa\nb0b\nccc\n" \
+"
+ aaa
+-b${CW}b${CR}b
++b${CW}0${CR}b
+ ccc
+"
+'
+
+test_expect_success 'diff-highlight does not highlight whole line' '
+	dh_test \
+		"aaa\nbbb\nccc\n" \
+		"aaa\n000\nccc\n"
+'
+
+test_expect_success 'diff-highlight does not highlight mismatched hunk size' '
+	dh_test \
+		"aaa\nbbb\n" \
+		"aaa\nb0b\nccc\n"
+'
+
+# TODO add multi-byte test
+
+test_done

@@ -0,0 +1,69 @@
+#!/bin/sh
+
+CURR_DIR=$(pwd)
+TEST_OUTPUT_DIRECTORY=$(pwd)
+TEST_DIRECTORY="$CURR_DIR"/../../../t
+DIFF_HIGHLIGHT="$CURR_DIR"/../diff-highlight
+
+CW="\033[7m"
+CR="\033[27m"
+
+export TEST_OUTPUT_DIRECTORY TEST_DIRECTORY CW CR
+
+dh_test() {
+	dh_diff_test "$@" &&
+	dh_commit_test "$@"
+}
+
+dh_diff_test() {
+	a="$1" b="$2"
+
+	printf "$a" >file
+	git add file
+
+	printf "$b" >file
+	git diff file >diff.raw
+
+	if test $# -eq 3
+	then
+		# remove last newline
+		head -n5 diff.raw | test_chomp_eof >diff.exp
+		printf "$3" >>diff.exp
+	else
+		cat diff.raw >diff.exp
+	fi
+
+	<diff.raw "$DIFF_HIGHLIGHT" >diff.act &&
+	test -s diff.act &&
+	diff diff.exp diff.act
+}
+
+dh_commit_test() {
+	a="$1" b="$2"
+
+	printf "$a" >file
+	git add file
+	git commit -m"Add a file" >/dev/null
+
+	printf "$b" >file
+	git commit -am"Update a file" >/dev/null
+
+	git show >commit.raw
+
+	if test "$#" = 3
+	then
+		# remove last newline
+		head -n11 commit.raw | test_chomp_eof >commit.exp
+		printf "$3" >>commit.exp
+	else
+		cat commit.raw >commit.exp
+	fi
+
+	<commit.raw "$DIFF_HIGHLIGHT" >commit.act &&
+	test -s commit.act &&
+	test_cmp commit.exp commit.act
+}
+
+test_chomp_eof() {
+	perl -pe 'chomp if eof'
+}