[NF] Added extends tests.

Belonging to [master]:
  - OpenModelica/OMCompiler#2317
  - OpenModelica/OpenModelica-testsuite#898

flattening/modelica/scodeinst/ExtendsShort1.mo

@@ -0,0 +1,25 @@
+// name: ExtendsShort1
+// keywords:
+// status: correct
+// cflags: -d=newInst
+//
+//
+
+package P
+  constant Integer n = 2;
+
+  model M
+    Integer x = n;
+  end M;
+end P;
+
+model ExtendsShort1
+  model M = P.M;
+  M m;
+end ExtendsShort1;
+
+// Result:
+// class ExtendsShort1
+//   Integer m.x = 2;
+// end ExtendsShort1;
+// endResult

flattening/modelica/scodeinst/ExtendsShort2.mo

@@ -0,0 +1,43 @@
+// name: ExtendsShort2
+// keywords:
+// status: correct
+// cflags: -d=newInst
+//
+//
+
+package P
+  function f
+    input Real x;
+    output Real y;
+  algorithm
+    y := f2(x);
+  end f;
+
+  function f2
+    input Real x;
+    output Real y = x * 2;
+  end f2;
+end P;
+
+model ExtendsShort2
+  function f = P.f;
+  Real x = f(2.0);
+end ExtendsShort2;
+
+// Result:
+// function P.f2
+//   input Real x;
+//   output Real y = x * 2.0;
+// end P.f2;
+//
+// function f
+//   input Real x;
+//   output Real y;
+// algorithm
+//   y := P.f2(x);
+// end f;
+//
+// class ExtendsShort2
+//   Real x = f(2.0);
+// end ExtendsShort2;
+// endResult

flattening/modelica/scodeinst/Makefile

@@ -242,6 +242,8 @@ ExtendSections.mo \
 ExtendSelf1.mo \
 ExtendSelf2.mo \
 ExtendSelf3.mo \
+ExtendsShort1.mo \
+ExtendsShort2.mo \
 ExtendsVisibility1.mo \
 ExtendsVisibility2.mo \
 ExtendsVisibility3.mo \