Tests: use test_cmp instead of diff where possible

Several old tests were written before test_cmp was introduced, convert
these to test_cmp.

If were are at it, fix the order of the arguments where necessary to
make expected come first, so the command shows how the test result
deviates from the correct output.

Signed-off-by: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

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.' \

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

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 \

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

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

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' \

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