Nicer error message when missing sql from layer options

Fixes #446

NEWS.md

@@ -4,6 +4,9 @@
 
 Released 2016-mm-dd
 
+Bug fixes:
+ - Nicer error message when missing sql from layer options #446
+
 
 ## 2.41.0
 

lib/cartodb/api/overviews_metadata_api.js

@@ -13,7 +13,7 @@ var affectedTableRegexCache = {
 };
 
 function prepareSql(sql) {
-    return sql
+    return sql && sql
         .replace(affectedTableRegexCache.bbox, 'ST_MakeEnvelope(0,0,0,0)')
         .replace(affectedTableRegexCache.scale_denominator, '0')
         .replace(affectedTableRegexCache.pixel_width, '1')

test/acceptance/regressions.js

@@ -0,0 +1,40 @@
+require('../support/test_helper');
+
+var assert = require('../support/assert');
+var TestClient = require('../support/test-client');
+
+describe('regressions', function() {
+
+    var ERROR_RESPONSE = {
+        status: 400,
+        headers: {
+            'Content-Type': 'application/json; charset=utf-8'
+        }
+    };
+
+    it('should expose a nice error when missing sql option', function(done) {
+        var mapConfig = {
+            version: '1.5.0',
+            layers: [
+                {
+                    "type": "cartodb",
+                    "options": {
+                        "cartocss": '#polygons { polygon-fill: red; }',
+                        "cartocss_version": "2.3.0"
+                    }
+                }
+            ]
+        };
+
+        var testClient = new TestClient(mapConfig, 1234);
+
+        testClient.getLayergroup(ERROR_RESPONSE, function(err, layergroupResult) {
+            assert.ok(!err, err);
+
+            assert.equal(layergroupResult.errors.length, 1);
+            assert.equal(layergroupResult.errors[0], 'Missing sql for layer 0 options');
+
+            testClient.drain(done);
+        });
+    });
+});