Periodic box size is specified by System rather than NonbondedForce

platforms/reference/tests/TestReferenceGBVIForce.cpp

@@ -101,7 +101,7 @@ void testCutoffAndPeriodic() {
     const double cutoffDistance = 3.0;
     const double boxSize = 10.0;
     nonbonded->setCutoffDistance(cutoffDistance);
-    nonbonded->setPeriodicBoxVectors(Vec3(boxSize, 0, 0), Vec3(0, boxSize, 0), Vec3(0, 0, boxSize));
+    system.setPeriodicBoxVectors(Vec3(boxSize, 0, 0), Vec3(0, boxSize, 0), Vec3(0, 0, boxSize));
     system.addForce(gbsa);
     system.addForce(nonbonded);
     vector<Vec3> positions(2);

platforms/reference/tests/TestReferenceNonbondedForce.cpp

@@ -335,7 +335,7 @@ void testPeriodic() {
     nonbonded->setNonbondedMethod(NonbondedForce::CutoffPeriodic);
     const double cutoff = 2.0;
     nonbonded->setCutoffDistance(cutoff);
-    nonbonded->setPeriodicBoxVectors(Vec3(4, 0, 0), Vec3(0, 4, 0), Vec3(0, 0, 4));
+    system.setPeriodicBoxVectors(Vec3(4, 0, 0), Vec3(0, 4, 0), Vec3(0, 0, 4));
     system.addForce(nonbonded);
     Context context(system, integrator, platform);
     vector<Vec3> positions(3);
@@ -368,7 +368,7 @@ void testEwald() {
     const double cutoff = 2.0;
     nonbonded->setCutoffDistance(cutoff);
     nonbonded->setEwaldErrorTolerance(TOL);
-    nonbonded->setPeriodicBoxVectors(Vec3(6, 0, 0), Vec3(0, 6, 0), Vec3(0, 0, 6));
+    system.setPeriodicBoxVectors(Vec3(6, 0, 0), Vec3(0, 6, 0), Vec3(0, 0, 6));
     system.addForce(nonbonded);
     Context context(system, integrator, platform);
     vector<Vec3> positions(2);