Adding quick test case for not-enough-args error

test/errorhandling/notenoughargs.mml

@@ -0,0 +1,15 @@
+{
+    "srs": "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over",
+    "Stylesheet": [
+        "notenoughargs.mss"
+    ],
+    "Layer": [{
+        "id": "world",
+        "name": "world",
+        "srs": "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over",
+        "Datasource": {
+            "file": "http://tilemill-data.s3.amazonaws.com/test_data/shape_demo.zip",
+            "type": "shape"
+        }
+    }]
+}

test/errorhandling/notenoughargs.mss

@@ -0,0 +1,8 @@
+#world {
+  ::outline {
+    line-color: darken(#85c5d3);
+    line-width: 2;
+    line-join: round;
+  }
+  polygon-fill: #fff;
+}