Added test

specs/data/box-mixed-attributes/box-mixed-attributes.mtl

@@ -0,0 +1,12 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl Material
+Ns 96.078431
+Ka 0.100000 0.000000 0.000000
+Kd 0.640000 0.640000 0.640000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.100000
+Ni 1.000000
+d 1.000000
+illum 2

specs/data/box-mixed-attributes/box-mixed-attributes.obj

@@ -0,0 +1,46 @@
+# Blender v2.78 (sub 0) OBJ File: ''
+# www.blender.org
+mtllib box-mixed-attributes.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 0.0000 0.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 1.0000
+vt 1.0000 0.0000
+vt 1.0000 1.0000
+vt 0.0000 0.0000
+vt 0.0000 1.0000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+usemtl Material
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3 4 8 7
+f 7/9/3 8/10/3 6/11/3 5/12/3
+f 5/13/4 6/14/4 2/15/4 1/16/4
+f 3//5 7//5 5//5 1//5
+f 8/19 4/6 2/15 6/20

specs/lib/loadObjSpec.js

@@ -32,6 +32,7 @@ var objMissingTextureUrl = 'specs/data/box-missing-texture/box-missing-texture.o
 var objSubdirectoriesUrl = 'specs/data/box-subdirectories/box-textured.obj';
 var objWindowsPathsUrl = 'specs/data/box-windows-paths/box-windows-paths.obj';
 var objComplexMaterialUrl = 'specs/data/box-complex-material/box-complex-material.obj';
+var objMixedAttributesUrl = 'specs/data/box-mixed-attributes/box-mixed-attributes.obj';
 var objInvalidContentsUrl = 'specs/data/box/box.mtl';
 var objInvalidUrl = 'invalid.obj';
 
@@ -409,6 +410,14 @@ describe('loadObj', function() {
             }), done).toResolve();
     });
 
+    it('discards faces that don\'t use the same attributes as other faces in the primitive', function(done) {
+        expect(loadObj(objMixedAttributesUrl, defaultOptions)
+            .then(function(data) {
+                var primitive = getPrimitives(data)[0];
+                expect(primitive.indices.length).toBe(18); // 3 faces removed
+            }), done).toResolve();
+    });
+
     it('throws when file has invalid contents', function(done) {
         expect(loadObj(objInvalidContentsUrl, defaultOptions), done).toRejectWith(RuntimeError);
     });