Resolve "Compile error in unit tests"

Closes #600 (closed)

tests/classic_src/AbsBeamline/DipoleFieldTest.cpp

@@ -88,6 +88,7 @@ TEST(Maxwell, Zeros)
 
     SBendRep* myMagnet = new SBendRep("myMagnet");
     myMagnet->BendBase::setFieldMapFN("1DPROFILE1-DEFAULT");
+    myMagnet->BendBase::setElementLength(0.2);
     myMagnet->BendBase::setDesignEnergy(10.0e6);
     myMagnet->BendBase::setBendAngle(0.523599);//30 degrees
     myMagnet->BendBase::setFullGap(0.04);