bash prompt: test untracked files status indicator with untracked dirs

The next commit will tweak the way __git_ps1() decides whether to display
the untracked files status indicator in the presence of untracked
directories.  Add tests to make sure it doesn't change current behavior,
in particular that an empty untracked directory doesn't trigger the
untracked files status indicator.

Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9903-bash-prompt.sh

@@ -397,6 +397,31 @@ test_expect_success 'prompt - untracked files status indicator - untracked files
 	test_cmp expected "$actual"
 '
 
+test_expect_success 'prompt - untracked files status indicator - empty untracked dir' '
+	printf " (master)" >expected &&
+	mkdir otherrepo/untracked-dir &&
+	test_when_finished "rm -rf otherrepo/untracked-dir" &&
+	(
+		GIT_PS1_SHOWUNTRACKEDFILES=y &&
+		cd otherrepo &&
+		__git_ps1 >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'prompt - untracked files status indicator - non-empty untracked dir' '
+	printf " (master %%)" >expected &&
+	mkdir otherrepo/untracked-dir &&
+	test_when_finished "rm -rf otherrepo/untracked-dir" &&
+	>otherrepo/untracked-dir/untracked-file &&
+	(
+		GIT_PS1_SHOWUNTRACKEDFILES=y &&
+		cd otherrepo &&
+		__git_ps1 >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
 test_expect_success 'prompt - untracked files status indicator - untracked files outside cwd' '
 	printf " (master %%)" >expected &&
 	(