Use mkdir() instead of !mkdir in test 73, it's more reliable.
diff --git a/src/testdir/test73.in b/src/testdir/test73.in
index 712e123..3518e80 100644
--- a/src/testdir/test73.in
+++ b/src/testdir/test73.in
@@ -22,7 +22,7 @@
:new
:let cwd=getcwd()
:let test_out = cwd . '/test.out'
-:silent !mkdir Xfind
+:call mkdir('Xfind')
:cd Xfind
:set path=
:find
@@ -45,9 +45,9 @@
:close
:new
:" We shouldn't find any file at this point, test.out must be empty.
-:silent !mkdir in
+:call mkdir('in')
:cd in
-:silent !mkdir path
+:call mkdir('path')
:exec "cd " . cwd
:e Xfind/file.txt
SHoly Grail:w
@@ -103,15 +103,15 @@
:"
:" x/bar/voyager.txt
:" y/bar/voyager.txt
-:silent !mkdir foo
+:call mkdir('foo')
:cd foo
-:silent !mkdir x
-:silent !mkdir y
+:call mkdir('x')
+:call mkdir('y')
:cd x
-:silent !mkdir bar
+:call mkdir('bar')
:cd ..
:cd y
-:silent !mkdir bar
+:call mkdir('bar')
:cd ..
:cd ..
:" We should now be in the Xfind directory