t1200: fix a timing dependent error

The fourth test of show-branch in t1200 test was failing but only
sometimes. It only failed when two commits created in an earlier
test had different timestamps. When they were created within the
same second, the actual output matched the expected output.

Fix this by using test_tick to force reliable timestamps and update
the expected output so it does not to depend on the commits made in
the same sacond.

Signed-off-by: Nanako Shiraishi <nanako3@lavabit.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/gitcore-tutorial.txt

@@ -1186,9 +1186,9 @@ $ git show-branch
 * [master] Some fun.
  ! [mybranch] Some work.
 --
- + [mybranch] Some work.
 *  [master] Some fun.
-*+ [mybranch^] Initial commit
+ + [mybranch] Some work.
+*+ [master^] Initial commit
 ------------
 
 Now we are ready to experiment with the merge by hand.

t/t1200-tutorial.sh

@@ -47,7 +47,8 @@ test_expect_success 'tree' '
 '
 
 test_expect_success 'git diff-index -p HEAD' '
-	tree=$(git write-tree)
+	test_tick &&
+	tree=$(git write-tree) &&
 	commit=$(echo "Initial commit" | git commit-tree $tree) &&
 	git update-ref HEAD $commit &&
 	git diff-index -p HEAD > diff.output &&
@@ -113,12 +114,14 @@ test_expect_success 'git branch' '
 test_expect_success 'git resolve now fails' '
 	git checkout mybranch &&
 	echo "Work, work, work" >>hello &&
+	test_tick &&
 	git commit -m "Some work." -i hello &&
 
 	git checkout master &&
 
 	echo "Play, play, play" >>hello &&
 	echo "Lots of fun" >>example &&
+	test_tick &&
 	git commit -m "Some fun." -i hello example &&
 
 	test_must_fail git merge -m "Merge work in mybranch" mybranch
@@ -141,6 +144,7 @@ cat > show-branch.expect << EOF
 EOF
 
 test_expect_success 'git show-branch' '
+	test_tick &&
 	git commit -m "Merge work in mybranch" -i hello &&
 	git show-branch --topo-order --more=1 master mybranch \
 		> show-branch.output &&
@@ -201,9 +205,9 @@ cat > show-branch4.expect << EOF
 * [master] Some fun.
  ! [mybranch] Some work.
 --
- + [mybranch] Some work.
 *  [master] Some fun.
-*+ [mybranch^] Initial commit
+ + [mybranch] Some work.
+*+ [master^] Initial commit
 EOF
 
 test_expect_success 'git show-branch (part 4)' '