See:

	https://github.com/lballabio/QuantLib/pull/507/

--- ql/termstructures/volatility/equityfx/fixedlocalvolsurface.cpp
+++ ql/termstructures/volatility/equityfx/fixedlocalvolsurface.cpp
@@ -132,7 +132,8 @@ namespace QuantLib {
 
         for (Size i=0; i < strikes_.size(); ++i)
             for (Size j=1; j<strikes_[i]->size(); j++) {
-                QL_REQUIRE(strikes_[i]->at(j)>=strikes_[i]->at(j-1),
+                QL_REQUIRE(strikes_[i]->at(j)>=strikes_[i]->at(j-1)
+                    || close_enough(strikes_[i]->at(j),strikes_[i]->at(j-1)),
                            "strikes must be sorted");
             }
     }
--- test-suite/hestonslvmodel.cpp
+++ test-suite/hestonslvmodel.cpp
@@ -2446,7 +2446,7 @@ void HestonSLVModelTest::testMoustacheGraph() {
         -0.0293,-0.0297,-0.0251,-0.0192,-0.0134,-0.0084,-0.0045,
         -0.0015, 0.0005, 0.0017, 0.0020
     };
-    const Real tol = 8e-3;
+    const Real tol = 1e-2;
 
     for (Size i=0; i < 18; ++i) {
         const Real dist = 10.0+5.0*i;
--- test-suite/fdheston.cpp	2018-05-21 08:58:38.000000000 -0400
+++ test-suite/fdheston.cpp	2018-07-20 18:51:34.213199000 -0400
@@ -469,5 +469,5 @@
              new FdHestonVanillaEngine(boost::shared_ptr<HestonModel>(
                                            new HestonModel(hestonProcess)),
-                                       500, 400, 3, 0,
+                                       4000, 400, 3, 0,
                                        FdmSchemeDesc::ExplicitEuler())));