add test_cmp function for test scripts

Many scripts compare actual and expected output using
"diff -u". This is nicer than "cmp" because the output shows
how the two differ. However, not all versions of diff
understand -u, leading to unnecessary test failure.

This adds a test_cmp function to the test scripts and
switches all "diff -u" invocations to use it. The function
uses the contents of "$GIT_TEST_CMP" to compare its
arguments; the default is "diff -u".

On systems with a less-capable diff, you can do:

  GIT_TEST_CMP=cmp make test

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

t/t0003-attributes.sh

@@ -11,7 +11,7 @@ attr_check () {
 
 	git check-attr test -- "$path" >actual &&
 	echo "$path: test: $2" >expect &&
-	diff -u expect actual
+	test_cmp expect actual
 
 }
 

t/t0022-crlf-rename.sh

@@ -26,7 +26,7 @@ test_expect_success 'diff -M' '
 	git diff-tree -M -r --name-status HEAD^ HEAD |
 	sed -e "s/R[0-9]*/RNUM/" >actual &&
 	echo "RNUM	sample	elpmas" >expect &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 

t/t1005-read-tree-reset.sh

@@ -24,7 +24,7 @@ test_expect_success 'setup' '
 test_expect_success 'reset should work' '
   git read-tree -u --reset HEAD^ &&
   git ls-files >actual &&
-  diff -u expect actual
+  test_cmp expect actual
 '
 
 test_done

t/t2200-add-update.sh

@@ -62,7 +62,7 @@ test_expect_success 'cache tree has not been corrupted' '
 	sed -e "s/ 0	/	/" >expect &&
 	git ls-tree -r $(git write-tree) |
 	sed -e "s/ blob / /" >current &&
-	diff -u expect current
+	test_cmp expect current
 
 '
 

t/t3001-ls-files-others-exclude.sh

@@ -97,7 +97,7 @@ cat > expect << EOF
 EOF
 
 test_expect_success 'git-status honours core.excludesfile' \
-	'diff -u expect output'
+	'test_cmp expect output'
 
 test_expect_success 'trailing slash in exclude allows directory match(1)' '
 

t/t3050-subprojects-fetch.sh

@@ -26,7 +26,7 @@ test_expect_success clone '
 		cd cloned &&
 		(git rev-parse HEAD; git ls-files -s) >../actual
 	) &&
-	diff -u expected actual
+	test_cmp expected actual
 '
 
 test_expect_success advance '
@@ -46,7 +46,7 @@ test_expect_success fetch '
 		git pull &&
 		(git rev-parse HEAD; git ls-files -s) >../actual
 	) &&
-	diff -u expected actual
+	test_cmp expected actual
 '
 
 test_done

t/t3060-ls-files-with-tree.sh

@@ -66,6 +66,6 @@ test_expect_success 'git -ls-files --with-tree should succeed from subdir' '
 cd ..
 test_expect_success \
     'git -ls-files --with-tree should add entries from named tree.' \
-    'diff -u expected output'
+    'test_cmp expected output'
 
 test_done

t/t3201-branch-contains.sh

@@ -31,7 +31,7 @@ test_expect_success 'branch --contains=master' '
 	{
 		echo "  master" && echo "* side"
 	} >expect &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 
@@ -41,7 +41,7 @@ test_expect_success 'branch --contains master' '
 	{
 		echo "  master" && echo "* side"
 	} >expect &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 
@@ -51,7 +51,7 @@ test_expect_success 'branch --contains=side' '
 	{
 		echo "* side"
 	} >expect &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 

t/t3404-rebase-interactive.sh

@@ -146,8 +146,8 @@ EOF
 test_expect_success 'stop on conflicting pick' '
 	git tag new-branch1 &&
 	! git rebase -i master &&
-	diff -u expect .git/.dotest-merge/patch &&
-	diff -u expect2 file1 &&
+	test_cmp expect .git/.dotest-merge/patch &&
+	test_cmp expect2 file1 &&
 	test 4 = $(grep -v "^#" < .git/.dotest-merge/done | wc -l) &&
 	test 0 = $(grep -c "^[^#]" < .git/.dotest-merge/git-rebase-todo)
 '

t/t3405-rebase-malformed.sh

@@ -41,8 +41,8 @@ test_expect_success rebase '
 	git rebase master side &&
 	git cat-file commit HEAD | sed -e "1,/^\$/d" >F1 &&
 
-	diff -u F0 F1 &&
-	diff -u F F0
+	test_cmp F0 F1 &&
+	test_cmp F F0
 '
 
 test_done

t/t3406-rebase-message.sh

@@ -37,7 +37,7 @@ test_expect_success 'rebase -m' '
 	git rebase -m master >report &&
 	sed -n -e "/^Already applied: /p" \
 		-e "/^Committed: /p" report >actual &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 

t/t3701-add-interactive.sh

@@ -24,7 +24,7 @@ EOF
 test_expect_success 'diff works (initial)' '
 	(echo d; echo 1) | git add -i >output &&
 	sed -ne "/new file/,/content/p" <output >diff &&
-	diff -u expected diff
+	test_cmp expected diff
 '
 test_expect_success 'revert works (initial)' '
 	git add file &&
@@ -57,7 +57,7 @@ EOF
 test_expect_success 'diff works (commit)' '
 	(echo d; echo 1) | git add -i >output &&
 	sed -ne "/^index/,/content/p" <output >diff &&
-	diff -u expected diff
+	test_cmp expected diff
 '
 test_expect_success 'revert works (commit)' '
 	git add file &&

t/t3902-quoted.sh

@@ -78,28 +78,28 @@ EOF
 
 test_expect_success 'check fully quoted output from ls-files' '
 
-	git ls-files >current && diff -u expect.quoted current
+	git ls-files >current && test_cmp expect.quoted current
 
 '
 
 test_expect_success 'check fully quoted output from diff-files' '
 
 	git diff --name-only >current &&
-	diff -u expect.quoted current
+	test_cmp expect.quoted current
 
 '
 
 test_expect_success 'check fully quoted output from diff-index' '
 
 	git diff --name-only HEAD >current &&
-	diff -u expect.quoted current
+	test_cmp expect.quoted current
 
 '
 
 test_expect_success 'check fully quoted output from diff-tree' '
 
 	git diff --name-only HEAD^ HEAD >current &&
-	diff -u expect.quoted current
+	test_cmp expect.quoted current
 
 '
 
@@ -111,28 +111,28 @@ test_expect_success 'setting core.quotepath' '
 
 test_expect_success 'check fully quoted output from ls-files' '
 
-	git ls-files >current && diff -u expect.raw current
+	git ls-files >current && test_cmp expect.raw current
 
 '
 
 test_expect_success 'check fully quoted output from diff-files' '
 
 	git diff --name-only >current &&
-	diff -u expect.raw current
+	test_cmp expect.raw current
 
 '
 
 test_expect_success 'check fully quoted output from diff-index' '
 
 	git diff --name-only HEAD >current &&
-	diff -u expect.raw current
+	test_cmp expect.raw current
 
 '
 
 test_expect_success 'check fully quoted output from diff-tree' '
 
 	git diff --name-only HEAD^ HEAD >current &&
-	diff -u expect.raw current
+	test_cmp expect.raw current
 
 '
 

t/t3903-stash.sh

@@ -34,7 +34,7 @@ EOF
 test_expect_success 'parents of stash' '
 	test $(git rev-parse stash^) = $(git rev-parse HEAD) &&
 	git diff stash^2..stash > output &&
-	diff -u output expect
+	test_cmp output expect
 '
 
 test_expect_success 'apply needs clean working directory' '

t/t4023-diff-rename-typechange.sh

@@ -57,7 +57,7 @@ test_expect_success 'cross renames to be detected for regular files' '
 		echo "R100	foo	bar"
 		echo "R100	bar	foo"
 	} | sort >expect &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 
@@ -68,7 +68,7 @@ test_expect_success 'cross renames to be detected for typechange' '
 		echo "R100	foo	bar"
 		echo "R100	bar	foo"
 	} | sort >expect &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 
@@ -79,7 +79,7 @@ test_expect_success 'moves and renames' '
 		echo "R100	foo	bar"
 		echo "T100	foo"
 	} | sort >expect &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 

t/t4024-diff-optimize-common.sh

@@ -150,7 +150,7 @@ test_expect_success 'diff -U0' '
 	do
 		git diff -U0 file-?$n
 	done | zc >actual &&
-	diff -u expect actual
+	test_cmp expect actual
 
 '
 

t/t4025-hunk-header.sh

@@ -37,7 +37,7 @@ test_expect_success 'hunk header truncation with an overly long line' '
 		echo " A $N$N$N$N$N$N$N$N$N2"
 		echo " L  $N$N$N$N$N$N$N$N$N1"
 	) >expected &&
-	diff -u actual expected
+	test_cmp actual expected
 
 '
 

t/t4027-diff-submodule.sh

@@ -37,17 +37,17 @@ test_expect_success setup '
 
 test_expect_success 'git diff --raw HEAD' '
 	git diff --raw --abbrev=40 HEAD >actual &&
-	diff -u expect actual
+	test_cmp expect actual
 '
 
 test_expect_success 'git diff-index --raw HEAD' '
 	git diff-index --raw HEAD >actual.index &&
-	diff -u expect actual.index
+	test_cmp expect actual.index
 '
 
 test_expect_success 'git diff-files --raw' '
 	git diff-files --raw >actual.files &&
-	diff -u expect actual.files
+	test_cmp expect actual.files
 '
 
 test_done

t/t4105-apply-fuzz.sh

@@ -9,7 +9,7 @@ dotest () {
 	test_expect_success "$name" "
 		git checkout-index -f -q -u file &&
 		git apply $* &&
-		diff -u expect file
+		test_cmp expect file
 	"
 }
 

t/t4125-apply-ws-fuzz.sh

@@ -56,7 +56,7 @@ test_expect_success nofix '
 	git apply --whitespace=nowarn patch-1 &&
 
 	# The result should obviously match.
-	diff -u file-1 file
+	test_cmp file-1 file
 '
 
 test_expect_success 'withfix (forward)' '
@@ -70,7 +70,7 @@ test_expect_success 'withfix (forward)' '
 	git apply --whitespace=fix patch-0 &&
 	git apply --whitespace=fix patch-1 &&
 
-	diff -u file-fixed file
+	test_cmp file-fixed file
 '
 
 test_expect_success 'withfix (backward)' '
@@ -91,12 +91,12 @@ test_expect_success 'withfix (backward)' '
 
 	sed -e /h/d file-fixed >fixed-head &&
 	sed -e /h/d file >file-head &&
-	diff -u fixed-head file-head &&
+	test_cmp fixed-head file-head &&
 
 	sed -n -e /h/p file-fixed >fixed-tail &&
 	sed -n -e /h/p file >file-tail &&
 
-	! diff -u fixed-tail file-tail
+	! test_cmp fixed-tail file-tail
 
 '
 

t/t4150-am-subdir.sh

@@ -22,14 +22,14 @@ test_expect_success 'am regularly from stdin' '
 	git checkout initial &&
 	git am <patchfile &&
 	git diff master >actual &&
-	diff -u expect actual
+	test_cmp expect actual
 '
 
 test_expect_success 'am regularly from file' '
 	git checkout initial &&
 	git am patchfile &&
 	git diff master >actual &&
-	diff -u expect actual
+	test_cmp expect actual
 '
 
 test_expect_success 'am regularly from stdin in subdirectory' '
@@ -41,7 +41,7 @@ test_expect_success 'am regularly from stdin in subdirectory' '
 		git am <../patchfile
 	) &&
 	git diff master>actual &&
-	diff -u expect actual
+	test_cmp expect actual
 '
 
 test_expect_success 'am regularly from file in subdirectory' '
@@ -53,7 +53,7 @@ test_expect_success 'am regularly from file in subdirectory' '
 		git am ../patchfile
 	) &&
 	git diff master >actual &&
-	diff -u expect actual
+	test_cmp expect actual
 '
 
 test_expect_success 'am regularly from file in subdirectory with full path' '
@@ -66,7 +66,7 @@ test_expect_success 'am regularly from file in subdirectory with full path' '
 		git am "$P/patchfile"
 	) &&
 	git diff master >actual &&
-	diff -u expect actual
+	test_cmp expect actual
 '
 
 test_done

t/t4201-shortlog.sh

@@ -45,6 +45,6 @@ A U Thor (5):
 
 EOF
 
-test_expect_success 'shortlog wrapping' 'diff -u expect out'
+test_expect_success 'shortlog wrapping' 'test_cmp expect out'
 
 test_done