Ensure submodule updates are performed on first clone

tests/git.bats

@@ -218,6 +218,17 @@ function setup_submodule {
     [ -f /tmp/forgebuild-time ]
 }
 
+@test "submodule is updated on first clone is subupdates is enabled" {
+    setup_submodule
+    cd $SUBMODULE
+    echo "SUBUPDATE" > README
+    git add README
+    git commit -m "update commit"
+    touch $FORGEBUILDDIR/time.subupdates
+    $FORGEBUILD -b $FORGEBUILDDIR time
+    [[ "$(cat $FORGEBUILDDIR/.time/sub/README)" = "SUBUPDATE" ]]
+}
+
 @test "submodule update does not trigger task by default" {
     setup_submodule
     $FORGEBUILD -b $FORGEBUILDDIR time