diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index 36279d8..1f8d307 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -175,6 +175,7 @@
 	    test_packadd.res \
 	    test_paste.res \
 	    test_perl.res \
+	    test_preview.res \
 	    test_profile.res \
 	    test_python2.res \
 	    test_python3.res \
diff --git a/src/testdir/test_preview.vim b/src/testdir/test_preview.vim
new file mode 100644
index 0000000..91923fb
--- /dev/null
+++ b/src/testdir/test_preview.vim
@@ -0,0 +1,13 @@
+" Tests for the preview window
+
+func Test_Psearch()
+  " this used to cause ml_get errors
+  help
+  let wincount = winnr('$')
+  0f
+  ps.
+  call assert_equal(wincount + 1, winnr('$'))
+  pclose
+  call assert_equal(wincount, winnr('$'))
+  bwipe
+endfunc