[NF] Add if-equation branch selection tests.

Belonging to [master]:
  - OpenModelica/OMCompiler#2729
  - OpenModelica/OpenModelica-testsuite#1054

flattening/modelica/scodeinst/IfEquationEval1.mo

@@ -0,0 +1,23 @@
+// name: IfEquationEval1
+// keywords:
+// status: correct
+// cflags: -d=newInst
+//
+
+model IfEquationEval1
+  Real x;
+equation
+  if true then
+    x = 1;
+  else
+    x = 2;
+  end if;
+end IfEquationEval1;
+
+// Result:
+// class IfEquationEval1
+//   Real x;
+// equation
+//   x = 1.0;
+// end IfEquationEval1;
+// endResult

flattening/modelica/scodeinst/IfEquationEval2.mo

@@ -0,0 +1,25 @@
+// name: IfEquationEval2
+// keywords:
+// status: correct
+// cflags: -d=newInst
+//
+
+model IfEquationEval2
+  Real x;
+equation
+  if false then
+    x = 0;
+  elseif true then
+    x = 1;
+  else
+    x = 2;
+  end if;
+end IfEquationEval2;
+
+// Result:
+// class IfEquationEval2
+//   Real x;
+// equation
+//   x = 1.0;
+// end IfEquationEval2;
+// endResult

flattening/modelica/scodeinst/IfEquationEval3.mo

@@ -0,0 +1,29 @@
+// name: IfEquationEval3
+// keywords:
+// status: correct
+// cflags: -d=newInst
+//
+
+model IfEquationEval3
+  Real x;
+equation
+  if time < 1 then
+    x = 0;
+  elseif true then
+    x = 1;
+  else
+    x = 2;
+  end if;
+end IfEquationEval3;
+
+// Result:
+// class IfEquationEval3
+//   Real x;
+// equation
+//   if time < 1.0 then
+//     x = 0.0;
+//   else
+//     x = 1.0;
+//   end if;
+// end IfEquationEval3;
+// endResult

flattening/modelica/scodeinst/Makefile

@@ -493,6 +493,9 @@ IfEquation3.mo \
 IfEquation4.mo \
 IfEquation5.mo \
 IfEquation6.mo \
+IfEquationEval1.mo \
+IfEquationEval2.mo \
+IfEquationEval3.mo \
 IfExpression1.mo \
 IfExpression2.mo \
 IfExpression3.mo \