diff --git a/src/ext/unit_tests/extGerberImport.cc b/src/ext/unit_tests/extGerberImport.cc
index dd1b7b9b2..267aa15b5 100644
--- a/src/ext/unit_tests/extGerberImport.cc
+++ b/src/ext/unit_tests/extGerberImport.cc
@@ -83,16 +83,19 @@ TEST(6)
 
 TEST(7)
 {
+  test_is_long_runner ();
   run_test (_this, "pcb-1");
 }
 
 TEST(8)
 {
+  test_is_long_runner ();
   run_test (_this, "microchip-2");
 }
 
 TEST(9)
 {
+  test_is_long_runner ();
   run_test (_this, "microchip-3");
 }
 
@@ -118,6 +121,7 @@ TEST(13)
 
 TEST(14)
 {
+  test_is_long_runner ();
   run_test (_this, "gerbv_examples/amacro-ref");
 }
 
@@ -128,6 +132,7 @@ TEST(15)
 
 TEST(16)
 {
+  test_is_long_runner ();
   run_test (_this, "gerbv_examples/protel-pnp");
 }
 
@@ -168,16 +173,19 @@ TEST(23)
 
 TEST(24)
 {
+  test_is_long_runner ();
   run_test (_this, "sr-sample");
 }
 
 TEST(25)
 {
+  test_is_long_runner ();
   run_test (_this, "sr-sample2");
 }
 
 TEST(26)
 {
+  test_is_long_runner ();
   run_test (_this, "pos-neg");
 }
 
diff --git a/src/ext/unit_tests/unit_tests.pro b/src/ext/unit_tests/unit_tests.pro
index 2aaac91ad..148142adc 100644
--- a/src/ext/unit_tests/unit_tests.pro
+++ b/src/ext/unit_tests/unit_tests.pro
@@ -2,7 +2,7 @@
 DESTDIR_UT = $$OUT_PWD/../..
 DESTDIR = $$OUT_PWD/..
 
-TARGET = ant_tests
+TARGET = ext_tests
 
 include($$PWD/../../lib_ut.pri)
 
diff --git a/src/gsi/gsi.pro b/src/gsi/gsi.pro
index e3580d66b..6e190ecd3 100644
--- a/src/gsi/gsi.pro
+++ b/src/gsi/gsi.pro
@@ -1,54 +1,7 @@
 
-DESTDIR = $$OUT_PWD/..
-TARGET = klayout_gsi
+TEMPLATE = subdirs
+SUBDIRS = gsi gsi_test unit_tests
 
-include($$PWD/../lib.pri)
-
-DEFINES += MAKE_GSI_LIBRARY
-
-SOURCES = \
-  gsi.cc \
-  gsiClassBase.cc \
-  gsiClass.cc \
-  gsiDeclBasic.cc \
-  gsiDeclInternal.cc \
-  gsiExpression.cc \
-  gsiExternalMain.cc \
-  gsiInterpreter.cc \
-  gsiMethods.cc \
-  gsiInspector.cc \
-  gsiObject.cc \
-  gsiSerialisation.cc \
-  gsiTypes.cc \
-  gsiObjectHolder.cc \
-
-HEADERS = \
-  gsiCallback.h \
-  gsiCallbackVar.h \
-  gsiClassBase.h \
-  gsiClass.h \
-  gsiDeclBasic.h \
-  gsiDecl.h \
-  gsiExpression.h \
-  gsiExternalMain.h \
-  gsi.h \
-  gsiInspector.h \
-  gsiInterpreter.h \
-  gsiIterators.h \
-  gsiMethods.h \
-  gsiMethodsVar.h \
-  gsiObject.h \
-  gsiSerialisation.h \
-  gsiSignals.h \
-  gsiTypes.h \
-  gsiObjectHolder.h \
-    gsiCommon.h
-
-# Note: unlike other modules, the tl declarations have to go here
-# since gsi is dependent on tl
-SOURCES += gsiDeclTl.cc 
-
-INCLUDEPATH += $$TL_INC
-DEPENDPATH += $$TL_INC
-LIBS += -L$$DESTDIR -lklayout_tl
+gsi_test.depends += gsi
+unit_tests.depends += gsi gsi_test
 
diff --git a/src/gsi/gsi.cc b/src/gsi/gsi/gsi.cc
similarity index 100%
rename from src/gsi/gsi.cc
rename to src/gsi/gsi/gsi.cc
diff --git a/src/gsi/gsi.h b/src/gsi/gsi/gsi.h
similarity index 100%
rename from src/gsi/gsi.h
rename to src/gsi/gsi/gsi.h
diff --git a/src/gsi/gsi/gsi.pro b/src/gsi/gsi/gsi.pro
new file mode 100644
index 000000000..9b839c2f1
--- /dev/null
+++ b/src/gsi/gsi/gsi.pro
@@ -0,0 +1,54 @@
+
+DESTDIR = $$OUT_PWD/../..
+TARGET = klayout_gsi
+
+include($$PWD/../../lib.pri)
+
+DEFINES += MAKE_GSI_LIBRARY
+
+SOURCES = \
+  gsi.cc \
+  gsiClassBase.cc \
+  gsiClass.cc \
+  gsiDeclBasic.cc \
+  gsiDeclInternal.cc \
+  gsiExpression.cc \
+  gsiExternalMain.cc \
+  gsiInterpreter.cc \
+  gsiMethods.cc \
+  gsiInspector.cc \
+  gsiObject.cc \
+  gsiSerialisation.cc \
+  gsiTypes.cc \
+  gsiObjectHolder.cc \
+
+HEADERS = \
+  gsiCallback.h \
+  gsiCallbackVar.h \
+  gsiClassBase.h \
+  gsiClass.h \
+  gsiDeclBasic.h \
+  gsiDecl.h \
+  gsiExpression.h \
+  gsiExternalMain.h \
+  gsi.h \
+  gsiInspector.h \
+  gsiInterpreter.h \
+  gsiIterators.h \
+  gsiMethods.h \
+  gsiMethodsVar.h \
+  gsiObject.h \
+  gsiSerialisation.h \
+  gsiSignals.h \
+  gsiTypes.h \
+  gsiObjectHolder.h \
+  gsiCommon.h
+
+# Note: unlike other modules, the tl declarations have to go here
+# since gsi is dependent on tl
+SOURCES += gsiDeclTl.cc 
+
+INCLUDEPATH += $$TL_INC
+DEPENDPATH += $$TL_INC
+LIBS += -L$$DESTDIR -lklayout_tl
+
diff --git a/src/gsi/gsiCallback.h b/src/gsi/gsi/gsiCallback.h
similarity index 100%
rename from src/gsi/gsiCallback.h
rename to src/gsi/gsi/gsiCallback.h
diff --git a/src/gsi/gsiCallbackVar.h b/src/gsi/gsi/gsiCallbackVar.h
similarity index 100%
rename from src/gsi/gsiCallbackVar.h
rename to src/gsi/gsi/gsiCallbackVar.h
diff --git a/src/gsi/gsiClass.cc b/src/gsi/gsi/gsiClass.cc
similarity index 100%
rename from src/gsi/gsiClass.cc
rename to src/gsi/gsi/gsiClass.cc
diff --git a/src/gsi/gsiClass.h b/src/gsi/gsi/gsiClass.h
similarity index 100%
rename from src/gsi/gsiClass.h
rename to src/gsi/gsi/gsiClass.h
diff --git a/src/gsi/gsiClassBase.cc b/src/gsi/gsi/gsiClassBase.cc
similarity index 100%
rename from src/gsi/gsiClassBase.cc
rename to src/gsi/gsi/gsiClassBase.cc
diff --git a/src/gsi/gsiClassBase.h b/src/gsi/gsi/gsiClassBase.h
similarity index 100%
rename from src/gsi/gsiClassBase.h
rename to src/gsi/gsi/gsiClassBase.h
diff --git a/src/gsi/gsiCommon.h b/src/gsi/gsi/gsiCommon.h
similarity index 100%
rename from src/gsi/gsiCommon.h
rename to src/gsi/gsi/gsiCommon.h
diff --git a/src/gsi/gsiDecl.h b/src/gsi/gsi/gsiDecl.h
similarity index 100%
rename from src/gsi/gsiDecl.h
rename to src/gsi/gsi/gsiDecl.h
diff --git a/src/gsi/gsiDeclBasic.cc b/src/gsi/gsi/gsiDeclBasic.cc
similarity index 100%
rename from src/gsi/gsiDeclBasic.cc
rename to src/gsi/gsi/gsiDeclBasic.cc
diff --git a/src/gsi/gsiDeclBasic.h b/src/gsi/gsi/gsiDeclBasic.h
similarity index 100%
rename from src/gsi/gsiDeclBasic.h
rename to src/gsi/gsi/gsiDeclBasic.h
diff --git a/src/gsi/gsiDeclInternal.cc b/src/gsi/gsi/gsiDeclInternal.cc
similarity index 100%
rename from src/gsi/gsiDeclInternal.cc
rename to src/gsi/gsi/gsiDeclInternal.cc
diff --git a/src/gsi/gsiDeclTl.cc b/src/gsi/gsi/gsiDeclTl.cc
similarity index 100%
rename from src/gsi/gsiDeclTl.cc
rename to src/gsi/gsi/gsiDeclTl.cc
diff --git a/src/gsi/gsiEnums.h b/src/gsi/gsi/gsiEnums.h
similarity index 100%
rename from src/gsi/gsiEnums.h
rename to src/gsi/gsi/gsiEnums.h
diff --git a/src/gsi/gsiExpression.cc b/src/gsi/gsi/gsiExpression.cc
similarity index 100%
rename from src/gsi/gsiExpression.cc
rename to src/gsi/gsi/gsiExpression.cc
diff --git a/src/gsi/gsiExpression.h b/src/gsi/gsi/gsiExpression.h
similarity index 100%
rename from src/gsi/gsiExpression.h
rename to src/gsi/gsi/gsiExpression.h
diff --git a/src/gsi/gsiExternalMain.cc b/src/gsi/gsi/gsiExternalMain.cc
similarity index 100%
rename from src/gsi/gsiExternalMain.cc
rename to src/gsi/gsi/gsiExternalMain.cc
diff --git a/src/gsi/gsiExternalMain.h b/src/gsi/gsi/gsiExternalMain.h
similarity index 100%
rename from src/gsi/gsiExternalMain.h
rename to src/gsi/gsi/gsiExternalMain.h
diff --git a/src/gsi/gsiInspector.cc b/src/gsi/gsi/gsiInspector.cc
similarity index 100%
rename from src/gsi/gsiInspector.cc
rename to src/gsi/gsi/gsiInspector.cc
diff --git a/src/gsi/gsiInspector.h b/src/gsi/gsi/gsiInspector.h
similarity index 100%
rename from src/gsi/gsiInspector.h
rename to src/gsi/gsi/gsiInspector.h
diff --git a/src/gsi/gsiInterpreter.cc b/src/gsi/gsi/gsiInterpreter.cc
similarity index 100%
rename from src/gsi/gsiInterpreter.cc
rename to src/gsi/gsi/gsiInterpreter.cc
diff --git a/src/gsi/gsiInterpreter.h b/src/gsi/gsi/gsiInterpreter.h
similarity index 100%
rename from src/gsi/gsiInterpreter.h
rename to src/gsi/gsi/gsiInterpreter.h
diff --git a/src/gsi/gsiIterators.h b/src/gsi/gsi/gsiIterators.h
similarity index 100%
rename from src/gsi/gsiIterators.h
rename to src/gsi/gsi/gsiIterators.h
diff --git a/src/gsi/gsiMethods.cc b/src/gsi/gsi/gsiMethods.cc
similarity index 100%
rename from src/gsi/gsiMethods.cc
rename to src/gsi/gsi/gsiMethods.cc
diff --git a/src/gsi/gsiMethods.h b/src/gsi/gsi/gsiMethods.h
similarity index 100%
rename from src/gsi/gsiMethods.h
rename to src/gsi/gsi/gsiMethods.h
diff --git a/src/gsi/gsiMethodsVar.h b/src/gsi/gsi/gsiMethodsVar.h
similarity index 100%
rename from src/gsi/gsiMethodsVar.h
rename to src/gsi/gsi/gsiMethodsVar.h
diff --git a/src/gsi/gsiObject.cc b/src/gsi/gsi/gsiObject.cc
similarity index 100%
rename from src/gsi/gsiObject.cc
rename to src/gsi/gsi/gsiObject.cc
diff --git a/src/gsi/gsiObject.h b/src/gsi/gsi/gsiObject.h
similarity index 100%
rename from src/gsi/gsiObject.h
rename to src/gsi/gsi/gsiObject.h
diff --git a/src/gsi/gsiObjectHolder.cc b/src/gsi/gsi/gsiObjectHolder.cc
similarity index 100%
rename from src/gsi/gsiObjectHolder.cc
rename to src/gsi/gsi/gsiObjectHolder.cc
diff --git a/src/gsi/gsiObjectHolder.h b/src/gsi/gsi/gsiObjectHolder.h
similarity index 100%
rename from src/gsi/gsiObjectHolder.h
rename to src/gsi/gsi/gsiObjectHolder.h
diff --git a/src/gsi/gsiSerialisation.cc b/src/gsi/gsi/gsiSerialisation.cc
similarity index 100%
rename from src/gsi/gsiSerialisation.cc
rename to src/gsi/gsi/gsiSerialisation.cc
diff --git a/src/gsi/gsiSerialisation.h b/src/gsi/gsi/gsiSerialisation.h
similarity index 100%
rename from src/gsi/gsiSerialisation.h
rename to src/gsi/gsi/gsiSerialisation.h
diff --git a/src/gsi/gsiSignals.h b/src/gsi/gsi/gsiSignals.h
similarity index 100%
rename from src/gsi/gsiSignals.h
rename to src/gsi/gsi/gsiSignals.h
diff --git a/src/gsi/gsiTypes.cc b/src/gsi/gsi/gsiTypes.cc
similarity index 100%
rename from src/gsi/gsiTypes.cc
rename to src/gsi/gsi/gsiTypes.cc
diff --git a/src/gsi/gsiTypes.h b/src/gsi/gsi/gsiTypes.h
similarity index 100%
rename from src/gsi/gsiTypes.h
rename to src/gsi/gsi/gsiTypes.h
diff --git a/src/unit_tests/gsiTest.cc b/src/gsi/gsi_test/gsiTest.cc
similarity index 100%
rename from src/unit_tests/gsiTest.cc
rename to src/gsi/gsi_test/gsiTest.cc
diff --git a/src/unit_tests/gsiTest.h b/src/gsi/gsi_test/gsiTest.h
similarity index 98%
rename from src/unit_tests/gsiTest.h
rename to src/gsi/gsi_test/gsiTest.h
index 4ecf6e892..611430a66 100644
--- a/src/unit_tests/gsiTest.h
+++ b/src/gsi/gsi_test/gsiTest.h
@@ -33,6 +33,7 @@
 #include <memory>
 #include <cstdio>
 
+#include "gsiCommon.h"
 #include "tlVariant.h"
 #include "tlString.h"
 
@@ -57,7 +58,7 @@ enum Enum
  *  It provides instance counting and tracking of one instance.
  *  It provides copy semantics.
  */
-struct A
+struct GSI_PUBLIC A
   : public gsi::ObjectBase
 {
   /**
@@ -238,7 +239,7 @@ struct A
 };
 
 
-struct A_NC
+struct GSI_PUBLIC A_NC
   : public A
 {
   A_NC () : A () { }
@@ -252,7 +253,7 @@ private:
 };
 
 template<class Iter>
-struct ValueIter
+struct GSI_PUBLIC ValueIter
 {
 public:
   typedef typename std::iterator_traits<Iter> it_traits;
@@ -285,7 +286,7 @@ private:
 };
 
 template<class Iter>
-struct FreeIter
+struct GSI_PUBLIC FreeIter
 {
 public:
   typedef typename std::iterator_traits<Iter> it_traits;
@@ -361,7 +362,7 @@ private:
 };
 
 template<class Iter>
-struct FreeIterUsePtr
+struct GSI_PUBLIC FreeIterUsePtr
 {
 public:
   typedef typename std::iterator_traits<Iter> it_traits;
@@ -398,7 +399,7 @@ private:
   Iter mb, me;
 };
 
-struct B
+struct GSI_PUBLIC B
 {
   B (); 
   B (const B &d);
@@ -824,7 +825,7 @@ struct B
   static B *b_inst;
 };
 
-class C
+class GSI_PUBLIC C
 {
 public:
   virtual ~C () { }
@@ -849,7 +850,7 @@ public:
   static std::vector<int> m_v;
 };
 
-class C_P
+class GSI_PUBLIC C_P
   : public C
 {
 public:
@@ -861,7 +862,7 @@ public:
   gsi::Callback f_cb;
 };
 
-struct E 
+struct GSI_PUBLIC E
   : public gsi::ObjectBase
 {
   E ();
@@ -896,7 +897,7 @@ private:
 };
 
 //  Same as "E", but not based on ObjectBase
-struct F 
+struct GSI_PUBLIC F
 {
   F() : x(0) { }
   static const F *ic();
@@ -910,7 +911,7 @@ struct F
   static std::auto_ptr<F> f_inst;
 };
 
-struct G
+struct GSI_PUBLIC G
 {
   G () : m_iv (0) { }
   int iv() const { return m_iv; }
@@ -925,7 +926,7 @@ struct G
   std::string m_sv;
 };
 
-class X
+class GSI_PUBLIC X
   : public gsi::ObjectBase
 {
 public:
@@ -956,7 +957,7 @@ private:
   static std::auto_ptr<X> sp_a, sp_b;
 };
 
-class Y
+class GSI_PUBLIC Y
   : public X
 {
 public:
@@ -987,27 +988,27 @@ private:
   Y *mp_c;
 };
 
-class Y2
+class GSI_PUBLIC Y2
   : public X
 {
 public:
   int x1 () const { return 2; }
 };
 
-class Y3
+class GSI_PUBLIC Y3
   : public X
 {
 public:
   int x1 () const { return 3; }
 };
 
-class Y4
+class GSI_PUBLIC Y4
 {
 public:
   int x1 () const { return 4; }
 };
 
-class YY : public Y
+class GSI_PUBLIC YY : public Y
 {
 public:
   YY ();
@@ -1015,7 +1016,7 @@ public:
   virtual QString cls_name() const;
 };
 
-class Z
+class GSI_PUBLIC Z
 {
 public:
   Z ();
@@ -1030,7 +1031,7 @@ private:
   X *mp_x;
 };
     
-class Z_P
+class GSI_PUBLIC Z_P
   : public Z
 {
 public:
@@ -1043,7 +1044,7 @@ public:
   gsi::Callback f_cb;
 };
 
-class SQ
+class GSI_PUBLIC SQ
   : public QObject
 {
 Q_OBJECT
@@ -1069,7 +1070,7 @@ private:
   int m_tag;
 };
 
-class SE
+class GSI_PUBLIC SE
   : public tl::Object
 {
 public:
diff --git a/src/gsi/gsi_test/gsi_test.pro b/src/gsi/gsi_test/gsi_test.pro
new file mode 100644
index 000000000..bc44be6b8
--- /dev/null
+++ b/src/gsi/gsi_test/gsi_test.pro
@@ -0,0 +1,18 @@
+
+DESTDIR = $$OUT_PWD/../..
+TARGET = gsi_test
+
+include($$PWD/../../lib.pri)
+
+DEFINES += MAKE_GSI_LIBRARY
+
+SOURCES = \
+  gsiTest.cc \
+
+HEADERS = \
+  gsiTest.h \
+
+INCLUDEPATH += $$TL_INC $$GSI_INC
+DEPENDPATH += $$TL_INC $$GSI_INC
+LIBS += -L$$DESTDIR -lklayout_tl -lklayout_gsi
+
diff --git a/src/unit_tests/gsiExpression.cc b/src/gsi/unit_tests/gsiExpression.cc
similarity index 99%
rename from src/unit_tests/gsiExpression.cc
rename to src/gsi/unit_tests/gsiExpression.cc
index 1a54709a9..b9d53999b 100644
--- a/src/unit_tests/gsiExpression.cc
+++ b/src/gsi/unit_tests/gsiExpression.cc
@@ -23,6 +23,7 @@
 
 #include "gsiExpression.h"
 #include "gsiDecl.h"
+#include "gsiTest.h"
 #include "dbBox.h"
 #include "dbEdge.h"
 
diff --git a/src/gsi/unit_tests/unit_tests.pro b/src/gsi/unit_tests/unit_tests.pro
new file mode 100644
index 000000000..1c5c51f8f
--- /dev/null
+++ b/src/gsi/unit_tests/unit_tests.pro
@@ -0,0 +1,16 @@
+
+DESTDIR_UT = $$OUT_PWD/../..
+DESTDIR = $$OUT_PWD/..
+
+TARGET = gsi_tests
+
+include($$PWD/../../lib_ut.pri)
+
+SOURCES = \
+  gsiExpression.cc \
+
+INCLUDEPATH += $$TL_INC $$GSI_INC $$GSI_TEST_INC $$UT_INC $$DB_INC
+DEPENDPATH += $$TL_INC $$GSI_INC $$GSI_TEST_INC $$UT_INC $$DB_INC
+
+LIBS += -L$$DESTDIR_UT -lklayout_tl -lklayout_gsi -lgsi_test -lklayout_ut -lklayout_db
+
diff --git a/src/klayout.pri b/src/klayout.pri
index c75a1d3b9..e8c1b0a63 100644
--- a/src/klayout.pri
+++ b/src/klayout.pri
@@ -5,7 +5,8 @@ DB_INC = $$PWD/db/db
 DRC_INC = $$PWD/drc/drc
 EDT_INC = $$PWD/edt/edt
 EXT_INC = $$PWD/ext/ext
-GSI_INC = $$PWD/gsi
+GSI_INC = $$PWD/gsi/gsi
+GSI_TEST_INC = $$PWD/gsi/gsi_test
 GSIQT_INC = $$PWD/gsiqt
 IMG_INC = $$PWD/img
 LIB_INC = $$PWD/lib
diff --git a/src/unit_tests/unit_tests.pro b/src/unit_tests/unit_tests.pro
index 344729494..8a72f1421 100644
--- a/src/unit_tests/unit_tests.pro
+++ b/src/unit_tests/unit_tests.pro
@@ -8,12 +8,7 @@ TEMPLATE = app
 
 TARGET = ut_runner
 
-HEADERS = \
-  gsiTest.h
-
 SOURCES = \
-  gsiExpression.cc \
-  gsiTest.cc \
   imgObject.cc \
   layAnnotationShapes.cc \
   layBitmap.cc \
@@ -37,3 +32,8 @@ equals(HAVE_QT5, "1") {
   CONFIG += qtestlib
 }
 
+# TODO: remove later
+INCLUDEPATH += $$GSI_TEST_INC
+DEPENDPATH += $$GSI_TEST_INC
+LIBS += -L$$DESTDIR -lgsi_test
+