Get rid of the dependency to GNU diff in the tests

Now that "git diff" handles stdin and relative paths outside the
working tree correctly, we can convert all instances of "diff -u"
to "git diff".

This commit is really the result of

$ perl -pi.bak -e 's/diff -u/git diff/' $(git grep -l "diff -u" t/)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

(cherry picked from commit c699a40d68215c7e44a5b26117a35c8a56fbd387)

29 files changed, 110 insertions, 110 deletions

diff --git a/t/diff-lib.sh b/t/diff-lib.sh
index 745a1b031..4624fe654 100755
--- a/t/diff-lib.sh
+++ b/t/diff-lib.sh
@@ -11,7 +11,7 @@ compare_diff_raw () {
 
     sed -e "$sanitize_diff_raw" <"$1" >.tmp-1
     sed -e "$sanitize_diff_raw" <"$2" >.tmp-2
-    diff -u .tmp-1 .tmp-2 && rm -f .tmp-1 .tmp-2
+    git diff .tmp-1 .tmp-2 && rm -f .tmp-1 .tmp-2
 }
 
 sanitize_diff_raw_z='/^:/s/ '"$_x40"' '"$_x40"' \([A-Z]\)[0-9]*$/ X X \1#/'
@@ -23,7 +23,7 @@ compare_diff_raw_z () {
 
     tr '\0' '\012' <"$1" | sed -e "$sanitize_diff_raw_z" >.tmp-1
     tr '\0' '\012' <"$2" | sed -e "$sanitize_diff_raw_z" >.tmp-2
-    diff -u .tmp-1 .tmp-2 && rm -f .tmp-1 .tmp-2
+    git diff .tmp-1 .tmp-2 && rm -f .tmp-1 .tmp-2
 }
 
 compare_diff_patch () {
@@ -37,5 +37,5 @@ compare_diff_patch () {
 	/^[dis]*imilarity index [0-9]*%$/d
 	/^index [0-9a-f]*\.\.[0-9a-f]/d
     ' <"$2" >.tmp-2
-    diff -u .tmp-1 .tmp-2 && rm -f .tmp-1 .tmp-2
+    git diff .tmp-1 .tmp-2 && rm -f .tmp-1 .tmp-2
 }
diff --git a/t/t1000-read-tree-m-3way.sh b/t/t1000-read-tree-m-3way.sh
index d0af8c3d5..e26a36cf0 100755
--- a/t/t1000-read-tree-m-3way.sh
+++ b/t/t1000-read-tree-m-3way.sh
@@ -131,7 +131,7 @@ _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 
 check_result () {
     git-ls-files --stage | sed -e 's/ '"$_x40"' / X /' >current &&
-    diff -u expected current
+    git diff expected current
 }
 
 # This is done on an empty work directory, which is the normal
diff --git a/t/t1001-read-tree-m-2way.sh b/t/t1001-read-tree-m-2way.sh
index 75e4c9a88..030226bbf 100755
--- a/t/t1001-read-tree-m-2way.sh
+++ b/t/t1001-read-tree-m-2way.sh
@@ -33,7 +33,7 @@ compare_change () {
 	    -e '/^--- /d; /^+++ /d; /^@@ /d;' \
 	    -e 's/^\([-+][0-7][0-7][0-7][0-7][0-7][0-7]\) '"$_x40"' /\1 X /p' \
 	    "$1"
-	diff -u expected current
+	git diff expected current
 }
 
 check_cache_at () {
@@ -86,7 +86,7 @@ test_expect_success \
     'rm -f .git/index &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >1-3.out &&
-     diff -u M.out 1-3.out &&
+     git diff M.out 1-3.out &&
      check_cache_at bozbar dirty &&
      check_cache_at frotz dirty &&
      check_cache_at nitfol dirty'
@@ -101,7 +101,7 @@ test_expect_success \
      git-update-index --add yomin &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >4.out || return 1
-     diff -u M.out 4.out >4diff.out
+     git diff M.out 4.out >4diff.out
      compare_change 4diff.out expected &&
      check_cache_at yomin clean'
 
@@ -115,7 +115,7 @@ test_expect_success \
      echo yomin yomin >yomin &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >5.out || return 1
-     diff -u M.out 5.out >5diff.out
+     git diff M.out 5.out >5diff.out
      compare_change 5diff.out expected &&
      check_cache_at yomin dirty'
 
@@ -127,7 +127,7 @@ test_expect_success \
      git-update-index --add frotz &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >6.out &&
-     diff -u M.out 6.out &&
+     git diff M.out 6.out &&
      check_cache_at frotz clean'
 
 test_expect_success \
@@ -140,7 +140,7 @@ test_expect_success \
      echo frotz frotz >frotz &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >7.out &&
-     diff -u M.out 7.out &&
+     git diff M.out 7.out &&
      check_cache_at frotz dirty'
 
 test_expect_success \
@@ -171,7 +171,7 @@ test_expect_success \
      git-update-index --add rezrov &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >10.out &&
-     diff -u M.out 10.out'
+     git diff M.out 10.out'
 
 test_expect_success \
     '11 - dirty path removed.' \
@@ -216,7 +216,7 @@ test_expect_success \
      git-update-index --add nitfol &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >14.out || return 1
-     diff -u M.out 14.out >14diff.out
+     git diff M.out 14.out >14diff.out
      compare_change 14diff.out expected &&
      check_cache_at nitfol clean'
 
@@ -230,7 +230,7 @@ test_expect_success \
      echo nitfol nitfol nitfol >nitfol &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >15.out || return 1
-     diff -u M.out 15.out >15diff.out
+     git diff M.out 15.out >15diff.out
      compare_change 15diff.out expected &&
      check_cache_at nitfol dirty'
 
@@ -262,7 +262,7 @@ test_expect_success \
      git-update-index --add bozbar &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >18.out &&
-     diff -u M.out 18.out &&
+     git diff M.out 18.out &&
      check_cache_at bozbar clean'
 
 test_expect_success \
@@ -275,7 +275,7 @@ test_expect_success \
      echo gnusto gnusto >bozbar &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >19.out &&
-     diff -u M.out 19.out &&
+     git diff M.out 19.out &&
      check_cache_at bozbar dirty'
 
 test_expect_success \
@@ -287,7 +287,7 @@ test_expect_success \
      git-update-index --add bozbar &&
      read_tree_twoway $treeH $treeM &&
      git-ls-files --stage >20.out &&
-     diff -u M.out 20.out &&
+     git diff M.out 20.out &&
      check_cache_at bozbar dirty'
 
 test_expect_success \
@@ -337,7 +337,7 @@ test_expect_success \
      git-update-index --add DF &&
      read_tree_twoway $treeDF $treeDFDF &&
      git-ls-files --stage >DFDFcheck.out &&
-     diff -u DFDF.out DFDFcheck.out &&
+     git diff DFDF.out DFDFcheck.out &&
      check_cache_at DF/DF dirty &&
      :'
 
diff --git a/t/t1002-read-tree-m-u-2way.sh b/t/t1002-read-tree-m-u-2way.sh
index da3c81357..87fe993f5 100755
--- a/t/t1002-read-tree-m-u-2way.sh
+++ b/t/t1002-read-tree-m-u-2way.sh
@@ -16,7 +16,7 @@ compare_change () {
 	sed >current \
 	    -e '/^--- /d; /^+++ /d; /^@@ /d;' \
 	    -e 's/^\(.[0-7][0-7][0-7][0-7][0-7][0-7]\) '"$_x40"' /\1 X /' "$1"
-	diff -u expected current
+	git diff expected current
 }
 
 check_cache_at () {
diff --git a/t/t1300-repo-config.sh b/t/t1300-repo-config.sh
index 49b5666b3..84a59397b 100755
--- a/t/t1300-repo-config.sh
+++ b/t/t1300-repo-config.sh
@@ -368,12 +368,12 @@ cat > expect << EOF
 weird
 EOF
 
-test_expect_success "rename succeeded" "diff -u expect .git/config"
+test_expect_success "rename succeeded" "git diff expect .git/config"
 
 test_expect_failure "rename non-existing section" \
 	'git-config --rename-section branch."world domination" branch.drei'
 
-test_expect_success "rename succeeded" "diff -u expect .git/config"
+test_expect_success "rename succeeded" "git diff expect .git/config"
 
 test_expect_success "rename another section" \
 	'git-config --rename-section branch."1 234 blabl/a" branch.drei'
@@ -389,7 +389,7 @@ cat > expect << EOF
 weird
 EOF
 
-test_expect_success "rename succeeded" "diff -u expect .git/config"
+test_expect_success "rename succeeded" "git diff expect .git/config"
 
 test_expect_success numbers '
 
diff --git a/t/t3001-ls-files-others-exclude.sh b/t/t3001-ls-files-others-exclude.sh
index 6979b7c1c..db7a847a5 100755
--- a/t/t3001-ls-files-others-exclude.sh
+++ b/t/t3001-ls-files-others-exclude.sh
@@ -65,7 +65,7 @@ test_expect_success \
        --exclude-per-directory=.gitignore \
        --exclude-from=.git/ignore \
        >output &&
-     diff -u expect output'
+     git diff expect output'
 
 # Test \r\n (MSDOS-like systems)
 printf '*.1\r\n/*.3\r\n!*.6\r\n' >.gitignore
@@ -77,6 +77,6 @@ test_expect_success \
        --exclude-per-directory=.gitignore \
        --exclude-from=.git/ignore \
        >output &&
-     diff -u expect output'
+     git diff expect output'
 
 test_done
diff --git a/t/t3002-ls-files-dashpath.sh b/t/t3002-ls-files-dashpath.sh
index b42f1382b..cc8967d76 100755
--- a/t/t3002-ls-files-dashpath.sh
+++ b/t/t3002-ls-files-dashpath.sh
@@ -23,7 +23,7 @@ test_expect_success \
 test_expect_success \
     'git-ls-files without path restriction.' \
     'git-ls-files --others >output &&
-     diff -u output - <<EOF
+     git diff output - <<EOF
 --
 -foo
 output
@@ -34,7 +34,7 @@ EOF
 test_expect_success \
     'git-ls-files with path restriction.' \
     'git-ls-files --others path0 >output &&
-	diff -u output - <<EOF
+	git diff output - <<EOF
 path0
 EOF
 '
@@ -42,7 +42,7 @@ EOF
 test_expect_success \
     'git-ls-files with path restriction with --.' \
     'git-ls-files --others -- path0 >output &&
-	diff -u output - <<EOF
+	git diff output - <<EOF
 path0
 EOF
 '
@@ -50,7 +50,7 @@ EOF
 test_expect_success \
     'git-ls-files with path restriction with -- --.' \
     'git-ls-files --others -- -- >output &&
-	diff -u output - <<EOF
+	git diff output - <<EOF
 --
 EOF
 '
@@ -58,7 +58,7 @@ EOF
 test_expect_success \
     'git-ls-files with no path restriction.' \
     'git-ls-files --others -- >output &&
-	diff -u output - <<EOF
+	git diff output - <<EOF
 --
 -foo
 output
diff --git a/t/t3100-ls-tree-restrict.sh b/t/t3100-ls-tree-restrict.sh
index 2ec06d3d3..e10749245 100755
--- a/t/t3100-ls-tree-restrict.sh
+++ b/t/t3100-ls-tree-restrict.sh
@@ -35,7 +35,7 @@ _x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
 _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 test_output () {
     sed -e "s/ $_x40	/ X	/" <current >check
-    diff -u expected check
+    git diff expected check
 }
 
 test_expect_success \
diff --git a/t/t3101-ls-tree-dirname.sh b/t/t3101-ls-tree-dirname.sh
index d78deb1e7..087929a4b 100755
--- a/t/t3101-ls-tree-dirname.sh
+++ b/t/t3101-ls-tree-dirname.sh
@@ -43,7 +43,7 @@ _x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
 _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 test_output () {
     sed -e "s/ $_x40	/ X	/" <current >check
-    diff -u expected check
+    git diff expected check
 }
 
 test_expect_success \
diff --git a/t/t3300-funny-names.sh b/t/t3300-funny-names.sh
index c12270efa..b5a1400e1 100755
--- a/t/t3300-funny-names.sh
+++ b/t/t3300-funny-names.sh
@@ -35,7 +35,7 @@ no-funny' >expected
 test_expect_success 'git-ls-files no-funny' \
 	'git-update-index --add "$p0" "$p2" &&
 	git-ls-files >current &&
-	diff -u expected current'
+	git diff expected current'
 
 t0=`git-write-tree`
 echo "$t0" >t0
@@ -48,14 +48,14 @@ EOF
 test_expect_success 'git-ls-files with-funny' \
 	'git-update-index --add "$p1" &&
 	git-ls-files >current &&
-	diff -u expected current'
+	git diff expected current'
 
 echo 'just space
 no-funny
 tabs	," (dq) and spaces' >expected
 test_expect_success 'git-ls-files -z with-funny' \
 	'git-ls-files -z | tr \\0 \\012 >current &&
-	diff -u expected current'
+	git diff expected current'
 
 t1=`git-write-tree`
 echo "$t1" >t1
@@ -67,28 +67,28 @@ no-funny
 EOF
 test_expect_success 'git-ls-tree with funny' \
 	'git-ls-tree -r $t1 | sed -e "s/^[^	]*	//" >current &&
-	 diff -u expected current'
+	 git diff expected current'
 
 cat > expected <<\EOF
 A	"tabs\t,\" (dq) and spaces"
 EOF
 test_expect_success 'git-diff-index with-funny' \
 	'git-diff-index --name-status $t0 >current &&
-	diff -u expected current'
+	git diff expected current'
 
 test_expect_success 'git-diff-tree with-funny' \
 	'git-diff-tree --name-status $t0 $t1 >current &&
-	diff -u expected current'
+	git diff expected current'
 
 echo 'A
 tabs	," (dq) and spaces' >expected
 test_expect_success 'git-diff-index -z with-funny' \
 	'git-diff-index -z --name-status $t0 | tr \\0 \\012 >current &&
-	diff -u expected current'
+	git diff expected current'
 
 test_expect_success 'git-diff-tree -z with-funny' \
 	'git-diff-tree -z --name-status $t0 $t1 | tr \\0 \\012 >current &&
-	diff -u expected current'
+	git diff expected current'
 
 cat > expected <<\EOF
 CNUM	no-funny	"tabs\t,\" (dq) and spaces"
@@ -96,7 +96,7 @@ EOF
 test_expect_success 'git-diff-tree -C with-funny' \
 	'git-diff-tree -C --find-copies-harder --name-status \
 		$t0 $t1 | sed -e 's/^C[0-9]*/CNUM/' >current &&
-	diff -u expected current'
+	git diff expected current'
 
 cat > expected <<\EOF
 RNUM	no-funny	"tabs\t,\" (dq) and spaces"
@@ -105,7 +105,7 @@ test_expect_success 'git-diff-tree delete with-funny' \
 	'git-update-index --force-remove "$p0" &&
 	git-diff-index -M --name-status \
 		$t0 | sed -e 's/^R[0-9]*/RNUM/' >current &&
-	diff -u expected current'
+	git diff expected current'
 
 cat > expected <<\EOF
 diff --git a/no-funny "b/tabs\t,\" (dq) and spaces"
@@ -116,7 +116,7 @@ EOF
 test_expect_success 'git-diff-tree delete with-funny' \
 	'git-diff-index -M -p $t0 |
 	 sed -e "s/index [0-9]*%/index NUM%/" >current &&
-	 diff -u expected current'
+	 git diff expected current'
 
 chmod +x "$p1"
 cat > expected <<\EOF
@@ -130,7 +130,7 @@ EOF
 test_expect_success 'git-diff-tree delete with-funny' \
 	'git-diff-index -M -p $t0 |
 	 sed -e "s/index [0-9]*%/index NUM%/" >current &&
-	 diff -u expected current'
+	 git diff expected current'
 
 cat >expected <<\EOF
  "tabs\t,\" (dq) and spaces"
@@ -139,7 +139,7 @@ EOF
 test_expect_success 'git-diff-tree rename with-funny applied' \
 	'git-diff-index -M -p $t0 |
 	 git-apply --stat | sed -e "s/|.*//" -e "s/ *\$//" >current &&
-	 diff -u expected current'
+	 git diff expected current'
 
 cat > expected <<\EOF
  no-funny
@@ -149,12 +149,12 @@ EOF
 test_expect_success 'git-diff-tree delete with-funny applied' \
 	'git-diff-index -p $t0 |
 	 git-apply --stat | sed -e "s/|.*//" -e "s/ *\$//" >current &&
-	 diff -u expected current'
+	 git diff expected current'
 
 test_expect_success 'git-apply non-git diff' \
 	'git-diff-index -p $t0 |
 	 sed -ne "/^[-+@]/p" |
 	 git-apply --stat | sed -e "s/|.*//" -e "s/ *\$//" >current &&
-	 diff -u expected current'
+	 git diff expected current'
 
 test_done
diff --git a/t/t3900-i18n-commit.sh b/t/t3900-i18n-commit.sh
index e54fe0f40..ffddb68db 100755
--- a/t/t3900-i18n-commit.sh
+++ b/t/t3900-i18n-commit.sh
@@ -9,7 +9,7 @@ test_description='commit and log output encodings'
 
 compare_with () {
 	git-show -s $1 | sed -e '1,/^$/d' -e 's/^    //' -e '$d' >current &&
-	diff -u current "$2"
+	git diff current "$2"
 }
 
 test_expect_success setup '
diff --git a/t/t4006-diff-mode.sh b/t/t4006-diff-mode.sh
index ca342f48a..e72c6fd1b 100755
--- a/t/t4006-diff-mode.sh
+++ b/t/t4006-diff-mode.sh
@@ -38,7 +38,7 @@ echo ":100644 100755 X X M	rezrov" >expected
 
 test_expect_success \
     'verify' \
-    'diff -u expected check'
+    'git diff expected check'
 
 test_done
 
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 3d85ceaae..9f54af5a1 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -111,7 +111,7 @@ do
 		} >"$actual" &&
 		if test -f "$expect"
 		then
-			diff -u "$expect" "$actual" &&
+			git diff "$expect" "$actual" &&
 			rm -f "$actual"
 		else
 			# this is to help developing new tests.
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index adf4993ba..930e209d3 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -43,13 +43,13 @@ index adf3937..6edc172 100644
 EOF
 
 git-diff > out
-test_expect_success "Ray's example without options" 'diff -u expect out'
+test_expect_success "Ray's example without options" 'git diff expect out'
 
 git-diff -w > out
-test_expect_success "Ray's example with -w" 'diff -u expect out'
+test_expect_success "Ray's example with -w" 'git diff expect out'
 
 git-diff -b > out
-test_expect_success "Ray's example with -b" 'diff -u expect out'
+test_expect_success "Ray's example with -b" 'git diff expect out'
 
 tr 'Q' '\015' << EOF > x
 whitespace at beginning
@@ -90,14 +90,14 @@ index d99af23..8b32fb5 100644
 +CR at end
 EOF
 git-diff > out
-test_expect_success 'another test, without options' 'diff -u expect out'
+test_expect_success 'another test, without options' 'git diff expect out'
 
 cat << EOF > expect
 diff --git a/x b/x
 index d99af23..8b32fb5 100644
 EOF
 git-diff -w > out
-test_expect_success 'another test, with -w' 'diff -u expect out'
+test_expect_success 'another test, with -w' 'git diff expect out'
 
 tr 'Q' '\015' << EOF > expect
 diff --git a/x b/x
@@ -115,6 +115,6 @@ index d99af23..8b32fb5 100644
  CR at endQ
 EOF
 git-diff -b > out
-test_expect_success 'another test, with -b' 'diff -u expect out'
+test_expect_success 'another test, with -b' 'git diff expect out'
 
 test_done
diff --git a/t/t4016-diff-quote.sh b/t/t4016-diff-quote.sh
index 2e7cd5f25..5dbdc0c9f 100755
--- a/t/t4016-diff-quote.sh
+++ b/t/t4016-diff-quote.sh
@@ -49,7 +49,7 @@ cat >expect <<\EOF
 EOF
 test_expect_success 'git diff --summary -M HEAD' '
 	git diff --summary -M HEAD >actual &&
-	diff -u expect actual
+	git diff expect actual
 '
 
 cat >expect <<\EOF
@@ -64,7 +64,7 @@ cat >expect <<\EOF
 EOF
 test_expect_success 'git diff --stat -M HEAD' '
 	git diff --stat -M HEAD >actual &&
-	diff -u expect actual
+	git diff expect actual
 '
 
 test_done
diff --git a/t/t4100-apply-stat.sh b/t/t4100-apply-stat.sh
index 6579f06b0..7b81c32e5 100755
--- a/t/t4100-apply-stat.sh
+++ b/t/t4100-apply-stat.sh
@@ -11,37 +11,37 @@ test_description='git-apply --stat --summary test.
 test_expect_success \
     'rename' \
     'git-apply --stat --summary <../t4100/t-apply-1.patch >current &&
-    diff -u ../t4100/t-apply-1.expect current'
+    git diff ../t4100/t-apply-1.expect current'
 
 test_expect_success \
     'copy' \
     'git-apply --stat --summary <../t4100/t-apply-2.patch >current &&
-    diff -u ../t4100/t-apply-2.expect current'
+    git diff ../t4100/t-apply-2.expect current'
 
 test_expect_success \
     'rewrite' \
     'git-apply --stat --summary <../t4100/t-apply-3.patch >current &&
-    diff -u ../t4100/t-apply-3.expect current'
+    git diff ../t4100/t-apply-3.expect current'
 
 test_expect_success \
     'mode' \
     'git-apply --stat --summary <../t4100/t-apply-4.patch >current &&
-    diff -u ../t4100/t-apply-4.expect current'
+    git diff ../t4100/t-apply-4.expect current'
 
 test_expect_success \
     'non git' \
     'git-apply --stat --summary <../t4100/t-apply-5.patch >current &&
-    diff -u ../t4100/t-apply-5.expect current'
+    git diff ../t4100/t-apply-5.expect current'
 
 test_expect_success \
     'non git' \
     'git-apply --stat --summary <../t4100/t-apply-6.patch >current &&
-    diff -u ../t4100/t-apply-6.expect current'
+    git diff ../t4100/t-apply-6.expect current'
 
 test_expect_success \
     'non git' \
     'git-apply --stat --summary <../t4100/t-apply-7.patch >current &&
-    diff -u ../t4100/t-apply-7.expect current'
+    git diff ../t4100/t-apply-7.expect current'
 
 test_done
 
diff --git a/t/t4104-apply-boundary.sh b/t/t4104-apply-boundary.sh
index 2ff800c23..a5fb3ea40 100755
--- a/t/t4104-apply-boundary.sh
+++ b/t/t4104-apply-boundary.sh
@@ -90,7 +90,7 @@ do
 				cat '"$kind-patch.$with"'
 				(exit 1)
 			} &&
-			diff -u '"$kind"'-expect victim
+			git diff '"$kind"'-expect victim
 		'
 	done
 done
@@ -108,7 +108,7 @@ do
 			cat '"$kind-ng.without"'
 			(exit 1)
 		} &&
-		diff -u '"$kind"'-expect victim
+		git diff '"$kind"'-expect victim
 	'
 done
 
diff --git a/t/t4115-apply-symlink.sh b/t/t4115-apply-symlink.sh
index d5f2cfb18..b947ed83b 100755
--- a/t/t4115-apply-symlink.sh
+++ b/t/t4115-apply-symlink.sh
@@ -33,7 +33,7 @@ test_expect_success 'apply symlink patch' '
 	git checkout side &&
 	git apply patch &&
 	git diff-files -p >patched &&
-	diff -u patch patched
+	git diff patch patched
 
 '
 
@@ -42,7 +42,7 @@ test_expect_success 'apply --index symlink patch' '
 	git checkout -f side &&
 	git apply --index patch &&
 	git diff-index --cached -p HEAD >patched &&
-	diff -u patch patched
+	git diff patch patched
 
 '
 
diff --git a/t/t4116-apply-reverse.sh b/t/t4116-apply-reverse.sh
index aa2c869e0..2685b2263 100755
--- a/t/t4116-apply-reverse.sh
+++ b/t/t4116-apply-reverse.sh
@@ -42,7 +42,7 @@ test_expect_success 'apply in reverse' '
 	git reset --hard second &&
 	git apply --reverse --binary --index patch &&
 	git diff >diff &&
-	diff -u /dev/null diff
+	git diff /dev/null diff
 
 '
 
diff --git a/t/t4117-apply-reject.sh b/t/t4117-apply-reject.sh
index b4de075a3..91931f0e3 100755
--- a/t/t4117-apply-reject.sh
+++ b/t/t4117-apply-reject.sh
@@ -54,7 +54,7 @@ test_expect_success 'apply without --reject should fail' '
 		exit 1
 	fi
 
-	diff -u file1 saved.file1
+	git diff file1 saved.file1
 '
 
 test_expect_success 'apply without --reject should fail' '
@@ -65,7 +65,7 @@ test_expect_success 'apply without --reject should fail' '
 		exit 1
 	fi
 
-	diff -u file1 saved.file1
+	git diff file1 saved.file1
 '
 
 test_expect_success 'apply with --reject should fail but update the file' '
@@ -79,7 +79,7 @@ test_expect_success 'apply with --reject should fail but update the file' '
 		exit 1
 	fi
 
-	diff -u file1 expected &&
+	git diff file1 expected &&
 
 	cat file1.rej &&
 
@@ -105,7 +105,7 @@ test_expect_success 'apply with --reject should fail but update the file' '
 		echo "file1 still exists?"
 		exit 1
 	}
-	diff -u file2 expected &&
+	git diff file2 expected &&
 
 	cat file2.rej &&
 
@@ -132,7 +132,7 @@ test_expect_success 'the same test with --verbose' '
 		echo "file1 still exists?"
 		exit 1
 	}
-	diff -u file2 expected &&
+	git diff file2 expected &&
 
 	cat file2.rej &&
 
@@ -151,7 +151,7 @@ test_expect_success 'apply cleanly with --verbose' '
 
 	git apply --verbose patch.1 &&
 
-	diff -u file1 clean
+	git diff file1 clean
 '
 
 test_done
diff --git a/t/t4118-apply-empty-context.sh b/t/t4118-apply-empty-context.sh
index 7309422fe..690a18200 100755
--- a/t/t4118-apply-empty-context.sh
+++ b/t/t4118-apply-empty-context.sh
@@ -37,7 +37,7 @@ test_expect_success 'apply --numstat' '
 		echo "0	1	file1" &&
 		echo "0	1	file2"
 	} >expect &&
-	diff -u expect actual
+	git diff expect actual
 
 '
 
@@ -47,8 +47,8 @@ test_expect_success 'apply --apply' '
 	cat file2.orig >file2 &&
 	git update-index file1 file2 &&
 	git apply --index diff.output &&
-	diff -u file1.mods file1 &&
-	diff -u file2.mods file2
+	git diff file1.mods file1 &&
+	git diff file2.mods file2
 '
 
 test_done
diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh
index 639d45fce..e081b32af 100755
--- a/t/t4200-rerere.sh
+++ b/t/t4200-rerere.sh
@@ -70,7 +70,7 @@ EOF
 
 git rerere diff > out
 
-test_expect_success 'rerere diff' 'diff -u expect out'
+test_expect_success 'rerere diff' 'git diff expect out'
 
 cat > expect << EOF
 a1
@@ -78,7 +78,7 @@ EOF
 
 git rerere status > out
 
-test_expect_success 'rerere status' 'diff -u expect out'
+test_expect_success 'rerere status' 'git diff expect out'
 
 test_expect_success 'commit succeeds' \
 	"git commit -q -a -m 'prefer first over second'"
@@ -94,7 +94,7 @@ test_expect_failure 'another conflicting merge' 'git pull . first'
 git show first:a1 | sed 's/To die: t/To die! T/' > expect
 test_expect_success 'rerere kicked in' "! grep ======= a1"
 
-test_expect_success 'rerere prefers first change' 'diff -u a1 expect'
+test_expect_success 'rerere prefers first change' 'git diff a1 expect'
 
 rm $rr/postimage
 echo "$sha1	a1" | tr '\012' '\0' > .git/rr-cache/MERGE_RR
diff --git a/t/t5400-send-pack.sh b/t/t5400-send-pack.sh
index 7d93d0d7c..fc4a12640 100755
--- a/t/t5400-send-pack.sh
+++ b/t/t5400-send-pack.sh
@@ -110,7 +110,7 @@ test_expect_success \
 	cd .. &&
 	git-update-ref refs/heads/master master^ &&
 	git-send-pack --force ./victim/.git/ master &&
-	! diff -u .git/refs/heads/master victim/.git/refs/heads/master
+	! git diff .git/refs/heads/master victim/.git/refs/heads/master
 '
 
 test_done
diff --git a/t/t5401-update-hooks.sh b/t/t5401-update-hooks.sh
index 0514056ca..460c9fd7f 100755
--- a/t/t5401-update-hooks.sh
+++ b/t/t5401-update-hooks.sh
@@ -51,12 +51,12 @@ test_expect_success 'hooks ran' '
 
 test_expect_success 'update hook arguments' '
 	echo refs/heads/master $commit0 $commit1 |
-	diff -u - victim/.git/update.args
+	git diff - victim/.git/update.args
 '
 
 test_expect_success 'post-update hook arguments' '
 	echo refs/heads/master |
-	diff -u - victim/.git/post-update.args
+	git diff - victim/.git/post-update.args
 '
 
 test_expect_failure 'update hook stdin is /dev/null' '
diff --git a/t/t6023-merge-file.sh b/t/t6023-merge-file.sh
index f3cd3dba4..c76fccfb5 100644
--- a/t/t6023-merge-file.sh
+++ b/t/t6023-merge-file.sh
@@ -63,7 +63,7 @@ test_expect_success "merge without conflict (missing LF at EOF)" \
 	"git-merge-file test2.txt orig.txt new2.txt"
 
 test_expect_success "merge result added missing LF" \
-	"diff -u test.txt test2.txt"
+	"git diff test.txt test2.txt"
 
 cp test.txt backup.txt
 test_expect_failure "merge with conflicts" \
@@ -86,7 +86,7 @@ non timebo mala, quoniam tu mecum es:
 virga tua et baculus tuus ipsa me consolata sunt.
 EOF
 
-test_expect_success "expected conflict markers" "diff -u test.txt expect.txt"
+test_expect_success "expected conflict markers" "git diff test.txt expect.txt"
 
 cp backup.txt test.txt
 test_expect_failure "merge with conflicts, using -L" \
@@ -110,7 +110,7 @@ virga tua et baculus tuus ipsa me consolata sunt.
 EOF
 
 test_expect_success "expected conflict markers, with -L" \
-	"diff -u test.txt expect.txt"
+	"git diff test.txt expect.txt"
 
 sed "s/ tu / TU /" < new1.txt > new5.txt
 test_expect_failure "conflict in removed tail" \
@@ -132,7 +132,7 @@ virga tua et baculus tuus ipsa me consolata sunt.
 >>>>>>> new5.txt
 EOF
 
-test_expect_success "expected conflict markers" "diff -u expect out"
+test_expect_success "expected conflict markers" "git diff expect out"
 
 test_done
 
diff --git a/t/t6024-recursive-merge.sh b/t/t6024-recursive-merge.sh
index 31b96257b..a39855613 100644
--- a/t/t6024-recursive-merge.sh
+++ b/t/t6024-recursive-merge.sh
@@ -70,7 +70,7 @@ G
 >>>>>>> G:a1
 EOF
 
-test_expect_success "result contains a conflict" "diff -u expect a1"
+test_expect_success "result contains a conflict" "git diff expect a1"
 
 git ls-files --stage > out
 cat > expect << EOF
@@ -79,6 +79,6 @@ cat > expect << EOF
 100644 fd7923529855d0b274795ae3349c5e0438333979 3	a1
 EOF
 
-test_expect_success "virtual trees were processed" "diff -u expect out"
+test_expect_success "virtual trees were processed" "git diff expect out"
 
 test_done
diff --git a/t/t6200-fmt-merge-msg.sh b/t/t6200-fmt-merge-msg.sh
index ea1402361..526d7d1c4 100755
--- a/t/t6200-fmt-merge-msg.sh
+++ b/t/t6200-fmt-merge-msg.sh
@@ -79,7 +79,7 @@ test_expect_success 'merge-msg test #1' '
 	git fetch . left &&
 
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	diff -u actual expected
+	git diff actual expected
 '
 
 cat >expected <<\EOF
@@ -92,7 +92,7 @@ test_expect_success 'merge-msg test #2' '
 	git fetch ../trash left &&
 
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	diff -u actual expected
+	git diff actual expected
 '
 
 cat >expected <<\EOF
@@ -115,7 +115,7 @@ test_expect_success 'merge-msg test #3' '
 	git fetch . left &&
 
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	diff -u actual expected
+	git diff actual expected
 '
 
 cat >expected <<\EOF
@@ -145,7 +145,7 @@ test_expect_success 'merge-msg test #4' '
 	git fetch . left right &&
 
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	diff -u actual expected
+	git diff actual expected
 '
 
 test_expect_success 'merge-msg test #5' '
@@ -157,7 +157,7 @@ test_expect_success 'merge-msg test #5' '
 	git fetch . left right &&
 
 	git fmt-merge-msg <.git/FETCH_HEAD >actual &&
-	diff -u actual expected
+	git diff actual expected
 '
 
 test_done
diff --git a/t/t9100-git-svn-basic.sh b/t/t9100-git-svn-basic.sh
index 7dcfc7e7d..eb628fe07 100755
--- a/t/t9100-git-svn-basic.sh
+++ b/t/t9100-git-svn-basic.sh
@@ -169,7 +169,7 @@ test_expect_success "$name" "
 	svn up '$SVN_TREE' &&
 	test -f '$SVN_TREE'/exec-2.sh &&
 	test ! -L '$SVN_TREE'/exec-2.sh &&
-	diff -u help $SVN_TREE/exec-2.sh"
+	git diff help $SVN_TREE/exec-2.sh"
 
 if test "$have_utf8" = t
 then
@@ -193,7 +193,7 @@ test_expect_success "$name" \
     "git-svn init $svnrepo && git-svn fetch &&
      git-rev-list --pretty=raw remotes/git-svn | grep ^tree | uniq > a &&
      git-rev-list --pretty=raw remotes/alt | grep ^tree | uniq > b &&
-     diff -u a b"
+     git diff a b"
 
 name='check imported tree checksums expected tree checksums'
 rm -f expected
@@ -211,7 +211,7 @@ tree d667270a1f7b109f5eb3aaea21ede14b56bfdd6e
 tree 8f51f74cf0163afc9ad68a4b1537288c4558b5a4
 EOF
 
-test_expect_success "$name" "diff -u a expected"
+test_expect_success "$name" "git diff a expected"
 
 test_expect_failure 'exit if remote refs are ambigious' "
         git-config --add svn-remote.svn.fetch \
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 970d68365..2337d83d3 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -74,7 +74,7 @@ EOF
 test_expect_success \
 	'A: verify commit' \
 	'git-cat-file commit master | sed 1d >actual &&
-	diff -u expect actual'
+	git diff expect actual'
 
 cat >expect <<EOF
 100644 blob file2
@@ -84,22 +84,22 @@ EOF
 test_expect_success \
 	'A: verify tree' \
 	'git-cat-file -p master^{tree} | sed "s/ [0-9a-f]*	/ /" >actual &&
-	 diff -u expect actual'
+	 git diff expect actual'
 
 echo "$file2_data" >expect
 test_expect_success \
 	'A: verify file2' \
-	'git-cat-file blob master:file2 >actual && diff -u expect actual'
+	'git-cat-file blob master:file2 >actual && git diff expect actual'
 
 echo "$file3_data" >expect
 test_expect_success \
 	'A: verify file3' \
-	'git-cat-file blob master:file3 >actual && diff -u expect actual'
+	'git-cat-file blob master:file3 >actual && git diff expect actual'
 
 printf "$file4_data" >expect
 test_expect_success \
 	'A: verify file4' \
-	'git-cat-file blob master:file4 >actual && diff -u expect actual'
+	'git-cat-file blob master:file4 >actual && git diff expect actual'
 
 cat >expect <<EOF
 :2 `git-rev-parse --verify master:file2`
@@ -109,7 +109,7 @@ cat >expect <<EOF
 EOF
 test_expect_success \
 	'A: verify marks output' \
-	'diff -u expect marks.out'
+	'git diff expect marks.out'
 
 ###
 ### series B
@@ -175,7 +175,7 @@ EOF
 test_expect_success \
 	'C: verify commit' \
 	'git-cat-file commit branch | sed 1d >actual &&
-	 diff -u expect actual'
+	 git diff expect actual'
 
 cat >expect <<EOF
 :000000 100755 0000000000000000000000000000000000000000 f1fb5da718392694d0076d677d6d0e364c79b0bc A	file2/newf
@@ -232,13 +232,13 @@ echo "$file5_data" >expect
 test_expect_success \
 	'D: verify file5' \
 	'git-cat-file blob branch:newdir/interesting >actual &&
-	 diff -u expect actual'
+	 git diff expect actual'
 
 echo "$file6_data" >expect
 test_expect_success \
 	'D: verify file6' \
 	'git-cat-file blob branch:newdir/exec.sh >actual &&
-	 diff -u expect actual'
+	 git diff expect actual'
 
 ###
 ### series E
@@ -274,7 +274,7 @@ EOF
 test_expect_success \
 	'E: verify commit' \
 	'git-cat-file commit branch | sed 1,2d >actual &&
-	diff -u expect actual'
+	git diff expect actual'
 
 ###
 ### series F
@@ -327,7 +327,7 @@ EOF
 test_expect_success \
 	'F: verify other commit' \
 	'git-cat-file commit other >actual &&
-	diff -u expect actual'
+	git diff expect actual'
 
 ###
 ### series G
@@ -405,7 +405,7 @@ echo "$file5_data" >expect
 test_expect_success \
 	'H: verify file' \
 	'git-cat-file blob H:h/e/l/lo >actual &&
-	 diff -u expect actual'
+	 git diff expect actual'
 
 ###
 ### series I
@@ -431,7 +431,7 @@ EOF
 test_expect_success \
 	'I: verify edge list' \
 	'sed -e s/pack-.*pack/pack-.pack/ edges.list >actual &&
-	 diff -u expect actual'
+	 git diff expect actual'
 
 ###
 ### series J