diff --git a/src/placing.js b/src/placing.js
index c2b761d..356e338 100644
--- a/src/placing.js
+++ b/src/placing.js
@@ -323,13 +323,13 @@ module.exports = (options) => {
       Object.keys(nodes).forEach(key => {
         const res = utils.isValid(nodes[key], NODE_DEF);
         if (res)
-          throw `Node '${key}' is invalid at key ${res}`;
+          throw `Node '${key}' is invalid at key '${res}'`;
       });
 
       links.forEach((link, i) => {
         const res = utils.isValid(link, LINK_DEF);
         if (res)
-          throw `Link ${i} (${link.from}->${link.to}) is invalid at key ${res}`;
+          throw `Link ${i} (${link.from}->${link.to}) is invalid at key '${res}'`;
       });
 
       Object.values(nodes).forEach(node => {
diff --git a/src/rendering.js b/src/rendering.js
index 80b2179..a1d3aca 100644
--- a/src/rendering.js
+++ b/src/rendering.js
@@ -325,13 +325,13 @@ module.exports = (options) => {
       Object.keys(nodes).forEach(key => {
         const res = utils.isValid(nodes[key], NODE_DEF);
         if (res)
-          throw `Node '${key}' is invalid at key ${res}`;
+          throw `Node '${key}' is invalid at key '${res}'`;
       });
 
       links.forEach((link, i) => {
         const res = utils.isValid(link, LINK_DEF);
         if (res)
-          throw `Link ${i} (${link.from}->${link.to}) is invalid at key ${res}`;
+          throw `Link ${i} (${link.from}->${link.to}) is invalid at key '${res}'`;
       });
 
       const bounds = self.getBounds(nodes);
diff --git a/test/placing.test.js b/test/placing.test.js
index c6627e2..4c39c01 100644
--- a/test/placing.test.js
+++ b/test/placing.test.js
@@ -403,19 +403,19 @@ describe('compute', () => {
   test('invalid node', () => {
     try {
       placing().compute({
-        'a': {name: 'a', x: 'hello'}
+        'a': {name: 'a'}, 'b': {name: 'b', x: 'hello'}
       }, []);
       fail('no error thrown');
     } catch (err) {
-      expect(err).toBe('Node \'a\' is invalid at key x');
+      expect(err).toBe('Node \'b\' is invalid at key \'x\'');
     }
   });
   test('invalid link', () => {
     try {
-      placing().compute({}, [{from: 'a', to: 5}]);
+      placing().compute({}, [{from: 'a', to: 'b'}, {from: 'a', to: 5}]);
       fail('no error thrown');
     } catch (err) {
-      expect(err).toBe('Link 0 (a->5) is invalid at key to');
+      expect(err).toBe('Link 1 (a->5) is invalid at key \'to\'');
     }
   });
   test('3 nodes no link', () => {
diff --git a/test/rendering.test.js b/test/rendering.test.js
index 8e618a1..20e2237 100644
--- a/test/rendering.test.js
+++ b/test/rendering.test.js
@@ -177,19 +177,19 @@ describe('compute', () => {
   test('invalid node', () => {
     try {
       rendering().compute({
-        'a': {name: 'a', icon: 5}
+        'a': {name: 'a', icon: '', x: 0, y: 0}, 'b': {name: 'b', icon: 5}
       }, []);
       fail('no error thrown');
     } catch (err) {
-      expect(err).toBe('Node \'a\' is invalid at key icon');
+      expect(err).toBe('Node \'b\' is invalid at key \'icon\'');
     }
   });
   test('invalid link', () => {
     try {
-      rendering().compute({}, [{from: 'a', to: 'b', type: 5}]);
+      rendering().compute({}, [{from: 'a', to: 'b'}, {from: 'a', to: 'b', type: 5}]);
       fail('no error thrown');
     } catch (err) {
-      expect(err).toBe('Link 0 (a->b) is invalid at key type');
+      expect(err).toBe('Link 1 (a->b) is invalid at key \'type\'');
     }
   });
 });
\ No newline at end of file