diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 70df15cbd8..ddcd5b0efb 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -127,7 +127,7 @@ cat >expected <<\EOF
 EOF
 test_expect_success \
     'validate git ls-files output for a known tree.' \
-    'diff current expected'
+    'test_cmp expected current'
 
 test_expect_success \
     'writing tree out with git write-tree.' \
@@ -147,7 +147,7 @@ cat >expected <<\EOF
 EOF
 test_expect_success \
     'git ls-tree output for a known tree.' \
-    'diff current expected'
+    'test_cmp expected current'
 
 # This changed in ls-tree pathspec change -- recursive does
 # not show tree nodes anymore.
@@ -166,7 +166,7 @@ cat >expected <<\EOF
 EOF
 test_expect_success \
     'git ls-tree -r output for a known tree.' \
-    'diff current expected'
+    'test_cmp expected current'
 
 # But with -r -t we can have both.
 test_expect_success \
@@ -187,7 +187,7 @@ cat >expected <<\EOF
 EOF
 test_expect_success \
     'git ls-tree -r output for a known tree.' \
-    'diff current expected'
+    'test_cmp expected current'
 
 test_expect_success \
     'writing partial tree out with git write-tree --prefix.' \
diff --git a/t/t1100-commit-tree-options.sh b/t/t1100-commit-tree-options.sh
index 7f7fc36734..c4414ff576 100755
--- a/t/t1100-commit-tree-options.sh
+++ b/t/t1100-commit-tree-options.sh
@@ -40,6 +40,6 @@ test_expect_success \
 
 test_expect_success \
     'compare commit' \
-    'diff expected commit'
+    'test_cmp expected commit'
 
 test_done
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index bd589268fc..54ba3df95f 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -137,7 +137,7 @@ $B $A $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150860 +0000
 EOF
 test_expect_success \
 	"verifying $m's log" \
-	"diff expect .git/logs/$m"
+	"test_cmp expect .git/logs/$m"
 rm -rf .git/$m .git/logs expect
 
 test_expect_success \
@@ -168,7 +168,7 @@ $B $A $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150980 +0000
 EOF
 test_expect_success \
 	"verifying $m's log" \
-	'diff expect .git/logs/$m'
+	'test_cmp expect .git/logs/$m'
 rm -f .git/$m .git/logs/$m expect
 
 git update-ref $m $D
@@ -272,7 +272,7 @@ $h_FIXED $h_MERGED $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117151100 +0000	c
 EOF
 test_expect_success \
 	'git commit logged updates' \
-	"diff expect .git/logs/$m"
+	"test_cmp expect .git/logs/$m"
 unset h_TEST h_OTHER h_FIXED h_MERGED
 
 test_expect_success \
diff --git a/t/t3000-ls-files-others.sh b/t/t3000-ls-files-others.sh
index bc0a351392..36eee0f8ae 100755
--- a/t/t3000-ls-files-others.sh
+++ b/t/t3000-ls-files-others.sh
@@ -42,7 +42,7 @@ test_expect_success \
 
 test_expect_success \
     'git ls-files --others should pick up symlinks.' \
-    'diff output expected1'
+    'test_cmp expected1 output'
 
 test_expect_success \
     'git ls-files --others --directory to show output.' \
@@ -51,6 +51,6 @@ test_expect_success \
 
 test_expect_success \
     'git ls-files --others --directory should not get confused.' \
-    'diff output expected2'
+    'test_cmp expected2 output'
 
 test_done
diff --git a/t/t3010-ls-files-killed-modified.sh b/t/t3010-ls-files-killed-modified.sh
index ec14040637..e4f02a0968 100755
--- a/t/t3010-ls-files-killed-modified.sh
+++ b/t/t3010-ls-files-killed-modified.sh
@@ -75,7 +75,7 @@ EOF
 
 test_expect_success \
     'validate git ls-files -k output.' \
-    'diff .output .expected'
+    'test_cmp .expected .output'
 
 test_expect_success \
     'git ls-files -m to show modified files.' \
@@ -91,6 +91,6 @@ EOF
 
 test_expect_success \
     'validate git ls-files -m output.' \
-    'diff .output .expected'
+    'test_cmp .expected .output'
 
 test_done
diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
index b7e362834b..e1ed073f95 100755
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -76,7 +76,7 @@ test_expect_success \
 
 test_expect_success \
     'git archive vs. git tar-tree' \
-    'diff b.tar b2.tar'
+    'test_cmp b.tar b2.tar'
 
 test_expect_success \
     'git archive in a bare repo' \
@@ -96,12 +96,12 @@ test_expect_success \
      "$TAR" xf b.tar -C extract a/a &&
      test-chmtime -v +0 extract/a/a |cut -f 1 >b.mtime &&
      echo "1117231200" >expected.mtime &&
-     diff expected.mtime b.mtime'
+     test_cmp expected.mtime b.mtime'
 
 test_expect_success \
     'git get-tar-commit-id' \
     'git get-tar-commit-id <b.tar >b.commitid &&
-     diff .git/$(git symbolic-ref HEAD) b.commitid'
+     test_cmp .git/$(git symbolic-ref HEAD) b.commitid'
 
 test_expect_success \
     'extract tar archive' \
@@ -110,7 +110,7 @@ test_expect_success \
 test_expect_success \
     'validate filenames' \
     '(cd b/a && find .) | sort >b.lst &&
-     diff a.lst b.lst'
+     test_cmp a.lst b.lst'
 
 test_expect_success \
     'validate file contents' \
@@ -127,7 +127,7 @@ test_expect_success \
 test_expect_success \
     'validate filenames with prefix' \
     '(cd c/prefix/a && find .) | sort >c.lst &&
-     diff a.lst c.lst'
+     test_cmp a.lst c.lst'
 
 test_expect_success \
     'validate file contents with prefix' \
@@ -148,8 +148,8 @@ test_expect_success \
      'validate substfile contents' \
      'git log --max-count=1 "--pretty=format:A${SUBSTFORMAT}O" HEAD \
       >f/a/substfile1.expected &&
-      diff f/a/substfile1.expected f/a/substfile1 &&
-      diff a/substfile2 f/a/substfile2
+      test_cmp f/a/substfile1.expected f/a/substfile1 &&
+      test_cmp a/substfile2 f/a/substfile2
 '
 
 test_expect_success \
@@ -160,8 +160,8 @@ test_expect_success \
      'validate substfile contents from archive with prefix' \
      'git log --max-count=1 "--pretty=format:A${SUBSTFORMAT}O" HEAD \
       >g/prefix/a/substfile1.expected &&
-      diff g/prefix/a/substfile1.expected g/prefix/a/substfile1 &&
-      diff a/substfile2 g/prefix/a/substfile2
+      test_cmp g/prefix/a/substfile1.expected g/prefix/a/substfile1 &&
+      test_cmp a/substfile2 g/prefix/a/substfile2
 '
 
 test_expect_success \
@@ -194,7 +194,7 @@ test_expect_success \
 test_expect_success \
     'validate filenames' \
     '(cd d/a && find .) | sort >d.lst &&
-     diff a.lst d.lst'
+     test_cmp a.lst d.lst'
 
 test_expect_success \
     'validate file contents' \
@@ -211,7 +211,7 @@ test_expect_success \
 test_expect_success \
     'validate filenames with prefix' \
     '(cd e/prefix/a && find .) | sort >e.lst &&
-     diff a.lst e.lst'
+     test_cmp a.lst e.lst'
 
 test_expect_success \
     'validate file contents with prefix' \
diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index 08d5b91c91..9523305304 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -88,7 +88,7 @@ cat >expected <<\EOF
 EOF
 test_expect_success \
     'Verify commandline' \
-    'diff commandline1 expected'
+    'test_cmp expected commandline1'
 
 cat >expected-show-all-headers <<\EOF
 0001-Second.patch