diff --git a/src/db/db/gsiDeclDbNetlist.cc b/src/db/db/gsiDeclDbNetlist.cc
index 97ff3a824..29f927cf7 100644
--- a/src/db/db/gsiDeclDbNetlist.cc
+++ b/src/db/db/gsiDeclDbNetlist.cc
@@ -39,6 +39,10 @@ Class<db::Pin> decl_dbPin ("db", "Pin",
   ) +
   gsi::method ("name", &db::Pin::name,
     "@brief Gets the name of the pin.\n"
+  ) +
+  gsi::method ("expanded_name", &db::Pin::expanded_name,
+    "@brief Gets the expanded name of the pin.\n"
+    "The expanded name is the name or a generic identifier made from the ID if the name is empty."
   ),
   "@brief A pin of a circuit.\n"
   "Pin objects are used to describe the outgoing pins of "
@@ -1010,6 +1014,11 @@ Class<db::Netlist> decl_dbNetlist ("db", "Netlist",
     "@brief Converts the netlist to a string representation.\n"
     "This method is intended for test purposes mainly."
   ) +
+  gsi::method ("from_s", &db::Netlist::from_string, gsi::arg ("str"),
+    "@brief Reads the netlist from a string representation.\n"
+    "This method is intended for test purposes mainly. It turns a string returned by \\to_s back into "
+    "a netlist. Note that the device classes must be created before as they are not persisted inside the string."
+  ) +
   gsi::method ("combine_devices", &db::Netlist::combine_devices,
     "@brief Combines devices where possible\n"
     "This method will combine devices that can be combined according "
diff --git a/src/db/db/gsiDeclDbNetlistCompare.cc b/src/db/db/gsiDeclDbNetlistCompare.cc
index 04d7c8f0c..50b91ae69 100644
--- a/src/db/db/gsiDeclDbNetlistCompare.cc
+++ b/src/db/db/gsiDeclDbNetlistCompare.cc
@@ -296,11 +296,10 @@ public:
 };
 
 }
-
 namespace gsi
 {
 
-Class<GenericNetlistCompareLogger> decl_GenericNetlistCompareLogger (decl_GenericNetlistCompareLogger, "db", "GenericNetlistCompareLogger",
+Class<GenericNetlistCompareLogger> decl_GenericNetlistCompareLogger ("db", "GenericNetlistCompareLogger",
   gsi::callback ("begin_netlist", &GenericNetlistCompareLogger::begin_netlist, &GenericNetlistCompareLogger::cb_begin_netlist, gsi::arg ("a"), gsi::arg ("b"),
     "@brief This function is called at the beginning of the compare process.\n"
     "This method is called once when the compare run begins.\n"
@@ -401,13 +400,13 @@ Class<GenericNetlistCompareLogger> decl_GenericNetlistCompareLogger (decl_Generi
   "This class has been introduced in version 0.26.\n"
 );
 
-db::NetlistComparer *make_comparer (db::NetlistCompareLogger *logger)
+static db::NetlistComparer *make_comparer (GenericNetlistCompareLogger *logger)
 {
   return new db::NetlistComparer (logger);
 }
 
 Class<db::NetlistComparer> decl_dbNetlistComparer ("db", "NetlistComparer",
-  gsi::constructor ("new", &make_comparer, gsi::arg ("logger", (db::NetlistCompareLogger *) 0),
+  gsi::constructor ("new", &make_comparer, gsi::arg ("logger", (GenericNetlistCompareLogger *) 0),
     "@brief Creates a new comparer object."
     "The logger is a delegate or event receiver which the comparer will send compare events to. "
     "See the class description for more details."
diff --git a/src/rba/unit_tests/rba.cc b/src/rba/unit_tests/rba.cc
index 5c6d4175e..cdc31958b 100644
--- a/src/rba/unit_tests/rba.cc
+++ b/src/rba/unit_tests/rba.cc
@@ -113,6 +113,7 @@ RUBYTEST (dbMatrix, "dbMatrix.rb")
 RUBYTEST (dbNetlist, "dbNetlist.rb")
 RUBYTEST (dbNetlistDeviceClasses, "dbNetlistDeviceClasses.rb")
 RUBYTEST (dbNetlistWriterTests, "dbNetlistWriterTests.rb")
+RUBYTEST (dbNetlistCompare, "dbNetlistCompare.rb")
 RUBYTEST (dbPathTest, "dbPathTest.rb")
 RUBYTEST (dbPCells, "dbPCells.rb")
 RUBYTEST (dbPointTest, "dbPointTest.rb")
diff --git a/testdata/ruby/dbNetlistCompare.rb b/testdata/ruby/dbNetlistCompare.rb
new file mode 100644
index 000000000..69d9f44ce
--- /dev/null
+++ b/testdata/ruby/dbNetlistCompare.rb
@@ -0,0 +1,747 @@
+# encoding: UTF-8
+
+# KLayout Layout Viewer
+# Copyright(C) 2006-2019 Matthias Koefferlein
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+#(at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+if !$:.member?(File::dirname($0))
+  $:.push(File::dirname($0))
+end
+
+load("test_prologue.rb")
+
+class NetlistCompareTestLogger < RBA::GenericNetlistCompareLogger
+
+  def initialize
+    @texts = []
+  end
+
+  def out(text)
+    @texts << text
+  end
+
+  def begin_circuit(a, b)
+    out("begin_circuit " + circuit2str(a) + " " + circuit2str(b))
+  end
+
+  def end_circuit(a, b, matching)
+    out("end_circuit " + circuit2str(a) + " " + circuit2str(b) + " " + (matching ? "MATCH" : "NOMATCH"))
+  end
+
+  def circuit_skipped(a, b)
+    out("circuit_skipped " + circuit2str(a) + " " + circuit2str(b))
+  end
+
+  def circuit_mismatch(a, b)
+    out("circuit_mismatch " + circuit2str(a) + " " + circuit2str(b))
+  end
+
+  def match_nets(a, b)
+    out("match_nets " + net2str(a) + " " + net2str(b))
+  end
+
+  def match_ambiguous_nets(a, b)
+    out("match_ambiguous_nets " + net2str(a) + " " + net2str(b))
+  end
+
+  def net_mismatch(a, b)
+    out("net_mismatch " + net2str(a) + " " + net2str(b))
+  end
+
+  def match_devices(a, b)
+    out("match_devices " + device2str(a) + " " + device2str(b))
+  end
+
+  def device_mismatch(a, b)
+    out("device_mismatch " + device2str(a) + " " + device2str(b))
+  end
+
+  def match_devices_with_different_parameters(a, b)
+    out("match_devices_with_different_parameters " + device2str(a) + " " + device2str(b))
+  end
+
+  def match_devices_with_different_device_classes(a, b)
+    out("match_devices_with_different_device_classes " + device2str(a) + " " + device2str(b))
+  end
+
+  def match_pins(a, b)
+    out("match_pins " + pin2str(a) + " " + pin2str(b))
+  end
+
+  def pin_mismatch(a, b)
+    out("pin_mismatch " + pin2str(a) + " " + pin2str(b))
+  end
+
+  def match_subcircuits(a, b)
+    out("match_subcircuits " + subcircuit2str(a) + " " + subcircuit2str(b))
+  end
+
+  def subcircuit_mismatch(a, b)
+    out("subcircuit_mismatch " + subcircuit2str(a) + " " + subcircuit2str(b))
+  end
+
+  def text
+    return @texts.join("\n") + "\n"
+  end
+
+  def clear
+    @texts = []
+  end
+
+  def circuit2str(x) 
+    return x ? x.name : "(null)"
+  end
+
+  def device2str(x) 
+    return x ? x.expanded_name : "(null)"
+  end
+
+  def net2str(x) 
+    return x ? x.expanded_name : "(null)"
+  end
+
+  def pin2str(x) 
+    return x ? x.expanded_name : "(null)"
+  end
+
+  def subcircuit2str(x) 
+    return x ? x.expanded_name : "(null)"
+  end
+
+end
+
+def prep_nl(nl, str)
+
+  dc = RBA::DeviceClassMOS3Transistor::new
+  dc.name = "PMOS"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassMOS3Transistor::new
+  dc.name = "NMOS"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassMOS3Transistor::new
+  dc.name = "PMOSB"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassMOS3Transistor::new
+  dc.name = "NMOSB"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassMOS4Transistor::new
+  dc.name = "PMOS4"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassMOS4Transistor::new
+  dc.name = "NMOS4"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassResistor::new
+  dc.name = "RES"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassCapacitor::new
+  dc.name = "CAP"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassInductor::new
+  dc.name = "IND"
+  nl.add(dc)
+
+  dc = RBA::DeviceClassDiode::new
+  dc.name = "DIODE"
+  nl.add(dc)
+
+  nl.from_s(str)
+
+end
+
+class NetlistCompare_TestClass < TestBase
+
+  def test_1
+
+    nls1 = <<"END"
+circuit INV($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1(S=VDD,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $2(S=VSS,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nls2 = <<"END"
+circuit INV($1=VDD,$2=IN,$3=VSS,$4=OUT);
+  device NMOS $1(S=OUT,G=IN,D=VSS)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2(S=VDD,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text, <<"END")
+begin_circuit INV INV
+match_nets VDD VDD
+match_nets VSS VSS
+match_nets OUT OUT
+match_nets IN IN
+match_pins $0 $1
+match_pins $1 $3
+match_pins $2 $0
+match_pins $3 $2
+match_devices $2 $1
+match_devices $1 $2
+end_circuit INV INV MATCH
+END
+
+    assert_equal(good, true)
+
+  end
+
+  def test_2
+
+    nls1 = <<"END"
+circuit INV($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1(S=VDD,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $2(S=VSS,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nls2 = <<"END"
+circuit INV($1=VDD,$2=IN,$3=VSS,$4=OUT);
+  device NMOSB $1(S=OUT,G=IN,D=VSS)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOSB $2(S=VDD,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    comp.same_device_classes(nl1.device_class_by_name("PMOS"), nl2.device_class_by_name("PMOSB"))
+
+    good = comp.compare(nl1, nl2)
+    assert_equal(good, false)
+
+    logger.clear
+    comp.same_device_classes(nl1.device_class_by_name("NMOS"), nl2.device_class_by_name("NMOSB"))
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text(), <<"END")
+begin_circuit INV INV
+match_nets VDD VDD
+match_nets VSS VSS
+match_nets OUT OUT
+match_nets IN IN
+match_pins $0 $1
+match_pins $1 $3
+match_pins $2 $0
+match_pins $3 $2
+match_devices $2 $1
+match_devices $1 $2
+end_circuit INV INV MATCH
+END
+
+    assert_equal(good, true)
+
+  end
+
+  def test_3
+
+    nls1 = <<"END"
+circuit INV($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1(S=VDD,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $2(S=VSS,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nls2 = <<"END"
+circuit INV($1=VDD,$2=IN,$3=VSS,$4=OUT);
+  device NMOS $1(S=OUT,G=IN,D=VSS)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2(S=VDD,G=IN,D=OUT)(L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    ca = nl1.circuit_by_name("INV")
+    cb = nl2.circuit_by_name("INV")
+    comp.same_nets(ca.net_by_name("VDD"), cb.net_by_name("VDD"))
+    comp.same_nets(ca.net_by_name("VSS"), cb.net_by_name("VSS"))
+
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text(), <<"END")
+begin_circuit INV INV
+match_nets OUT OUT
+match_nets IN IN
+match_pins $0 $1
+match_pins $1 $3
+match_pins $2 $0
+match_pins $3 $2
+match_devices $2 $1
+match_devices $1 $2
+end_circuit INV INV MATCH
+END
+
+    assert_equal(good, true)
+
+  end
+
+  def test_4
+
+    nls1 = <<"END"
+circuit BUF ($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1 (S=VDD,G=IN,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $2 (S=VSS,G=IN,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $3 (S=VDD,G=INT,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $4 (S=VSS,G=INT,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $5 (S=VDD,G=IN,D=INT2) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $6 (S=VSS,G=IN,D=INT2) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $7 (S=VDD,G=INT2,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $8 (S=VSS,G=INT2,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nls2 = <<"END"
+circuit BUF ($1=VDD,$2=IN,$3=VSS,$4=OUT);
+  device PMOS $1 (S=VDD,G=IN,D=$10) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2 (S=VDD,G=$10,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $3 (S=VDD,G=IN,D=$11) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $4 (S=VDD,G=$11,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $5 (S=$10,G=IN,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $6 (S=OUT,G=$10,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $7 (S=$11,G=IN,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $8 (S=OUT,G=$11,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text, <<"END")
+begin_circuit BUF BUF
+match_nets OUT OUT
+match_nets VDD VDD
+match_nets IN IN
+match_nets VSS VSS
+match_ambiguous_nets INT $10
+match_ambiguous_nets INT2 $11
+match_pins $0 $1
+match_pins $1 $3
+match_pins $2 $0
+match_pins $3 $2
+match_devices $1 $1
+match_devices $3 $2
+match_devices $5 $3
+match_devices $7 $4
+match_devices $2 $5
+match_devices $4 $6
+match_devices $6 $7
+match_devices $8 $8
+end_circuit BUF BUF MATCH
+END
+
+    assert_equal(good, true)
+
+  end
+
+  def test_5
+
+    nls1 = <<"END"
+circuit BUF ($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1 (S=VDD,G=IN,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $2 (S=VSS,G=IN,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $3 (S=VDD,G=INT,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $4 (S=VSS,G=INT,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $5 (S=VDD,G=IN,D=INT2) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $6 (S=VSS,G=IN,D=INT2) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $7 (S=VDD,G=INT2,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $8 (S=VSS,G=INT2,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nls2 = <<"END"
+circuit BUF ($1=VDD,$2=IN,$3=VSS,$4=OUT);
+  device PMOS $1 (S=VDD,G=IN,D=$10) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2 (S=VDD,G=$10,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $3 (S=VDD,G=IN,D=$11) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $4 (S=VDD,G=$11,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $5 (S=$10,G=IN,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $6 (S=OUT,G=$10,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $7 (S=$11,G=IN,D=VSS) (L=0.35,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $8 (S=OUT,G=$11,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    #  NOTE: adding this power hint makes the device class error harder to detect
+    ca = nl1.circuit_by_name("BUF")
+    cb = nl2.circuit_by_name("BUF")
+    comp.same_nets(ca.net_by_name("VDD"), cb.net_by_name("VDD"))
+    comp.same_nets(ca.net_by_name("VSS"), cb.net_by_name("VSS"))
+
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text, <<"END")
+begin_circuit BUF BUF
+match_nets OUT OUT
+match_nets IN IN
+match_ambiguous_nets INT $10
+match_nets INT2 $11
+match_pins $0 $1
+match_pins $1 $3
+match_pins $2 $0
+match_pins $3 $2
+match_devices $1 $1
+match_devices $3 $2
+match_devices $5 $3
+match_devices $7 $4
+match_devices $2 $5
+match_devices $4 $6
+match_devices_with_different_parameters $6 $7
+match_devices $8 $8
+end_circuit BUF BUF NOMATCH
+END
+
+    assert_equal(good, false)
+
+  end
+
+  def test_6
+
+    nls1 = <<"END"
+circuit BUF ($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1 (S=VDD,G=IN,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $2 (S=VSS,G=IN,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $3 (S=VDD,G=INT,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $4 (S=VSS,G=INT,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $5 (S=VDD,G=IN,D=INT2) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $6 (S=VSS,G=IN,D=INT2) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOSB $7 (S=VDD,G=INT2,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOSB $8 (S=VSS,G=INT2,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nls2 = <<"END"
+circuit BUF ($1=VDD,$2=IN,$3=VSS,$4=OUT);
+  device PMOS $1 (S=VDD,G=IN,D=$10) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2 (S=VDD,G=$10,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $3 (S=VDD,G=IN,D=$11) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $4 (S=VDD,G=$11,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $5 (S=$10,G=IN,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $6 (S=OUT,G=$10,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $7 (S=$11,G=IN,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOSB $8 (S=OUT,G=$11,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    #  NOTE: adding this power hint makes the device class error harder to detect
+    ca = nl1.circuit_by_name("BUF")
+    cb = nl2.circuit_by_name("BUF")
+    comp.same_nets(ca.net_by_name("VDD"), cb.net_by_name("VDD"))
+    comp.same_nets(ca.net_by_name("VSS"), cb.net_by_name("VSS"))
+
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text, <<"END")
+begin_circuit BUF BUF
+match_nets IN IN
+match_nets INT $10
+match_nets OUT OUT
+match_nets INT2 $11
+match_pins $0 $1
+match_pins $1 $3
+match_pins $2 $0
+match_pins $3 $2
+match_devices $1 $1
+match_devices $3 $2
+match_devices $5 $3
+match_devices_with_different_device_classes $7 $4
+match_devices $2 $5
+match_devices $4 $6
+match_devices $6 $7
+match_devices $8 $8
+end_circuit BUF BUF NOMATCH
+END
+
+    assert_equal(good, false)
+
+  end
+ 
+  def test_7
+
+    nls1 = <<"END"
+circuit BUF ($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1 (S=VDD,G=IN,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $2 (S=VSS,G=IN,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $3 (S=VDD,G=INT,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $4 (S=VSS,G=INT,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $5 (S=VDD,G=IN,D=INT2) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $6 (S=VSS,G=IN,D=INT2) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOSB $7 (S=VDD,G=INT2,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOSB $8 (S=VSS,G=INT2,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+END
+
+    nls2 = <<"END"
+circuit BUF ($1=VDD,$2=IN,$3=VSS,$4=OUT);
+  device PMOS $1 (S=VDD,G=IN,D=$10) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2 (S=VDD,G=$10,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $3 (S=VDD,G=IN,D=$11) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOSB $4 (S=VDD,G=$11,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $5 (S=$10,G=IN,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $6 (S=OUT,G=$10,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $7 (S=$11,G=IN,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOSB $8 (S=OUT,G=$11,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device RES $9 (A=$10,B=$11) (R=42);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    #  Forcing the power nets into equality makes the resistor error harder to detect
+    ca = nl1.circuit_by_name("BUF")
+    cb = nl2.circuit_by_name("BUF")
+    comp.same_nets(ca.net_by_name("VDD"), cb.net_by_name("VDD"))
+    comp.same_nets(ca.net_by_name("VSS"), cb.net_by_name("VSS"))
+
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text, <<"END")
+begin_circuit BUF BUF
+match_nets INT $10
+match_nets OUT OUT
+match_nets INT2 $11
+match_nets IN IN
+match_pins $0 $1
+match_pins $1 $3
+match_pins $2 $0
+match_pins $3 $2
+match_devices $1 $1
+match_devices $3 $2
+match_devices $5 $3
+match_devices $7 $4
+match_devices $2 $5
+match_devices $4 $6
+match_devices $6 $7
+match_devices $8 $8
+device_mismatch (null) $9
+end_circuit BUF BUF NOMATCH
+END
+
+    assert_equal(good, false)
+
+  end
+
+  def test_8
+
+    nls1 = <<"END"
+circuit INV ($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1 (S=VDD,G=IN,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $2 (S=VSS,G=IN,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+circuit TOP ($1=IN,$2=OUT,$3=VDD,$4=VSS);
+  subcircuit INV $1 ($1=IN,$2=INT,$3=VDD,$4=VSS);
+  subcircuit INV $2 ($1=INT,$2=OUT,$3=VDD,$4=VSS);
+end;
+END
+
+    nls2 = <<"END"
+circuit INVB ($1=VDD,$2=IN,$3=VSS,$4=OUT);
+  device NMOS $1 (S=OUT,G=IN,D=VSS) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2 (S=VDD,G=IN,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+circuit TOP ($1=OUT,$2=VDD,$3=IN,$4=VSS);
+  subcircuit INVB $1 ($1=VDD,$2=INT,$3=VSS,$4=OUT);
+  subcircuit INVB $2 ($1=VDD,$2=IN,$3=VSS,$4=INT);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    good = comp.compare(nl1, nl2)
+    assert_equal(good, false)
+
+    logger.clear
+    comp.same_circuits(nl1.circuit_by_name("INV"), nl2.circuit_by_name("INVB"))
+
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text, <<"END")
+begin_circuit INV INVB
+match_nets VDD VDD
+match_nets VSS VSS
+match_nets OUT OUT
+match_nets IN IN
+match_pins $0 $1
+match_pins $1 $3
+match_pins $2 $0
+match_pins $3 $2
+match_devices $2 $1
+match_devices $1 $2
+end_circuit INV INVB MATCH
+begin_circuit TOP TOP
+match_nets OUT OUT
+match_nets IN IN
+match_nets VSS VSS
+match_nets VDD VDD
+match_nets INT INT
+match_pins $0 $2
+match_pins $1 $0
+match_pins $2 $1
+match_pins $3 $3
+match_subcircuits $2 $1
+match_subcircuits $1 $2
+end_circuit TOP TOP MATCH
+END
+
+    assert_equal(good, true)
+  
+  end
+
+  def test_9
+
+    nls1 = <<"END"
+circuit NAND ($0=A,$1=B,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1 (S=VDD,G=A,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2 (S=VDD,G=B,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $3 (S=VSS,G=A,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $4 (S=INT,G=B,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+circuit TOP ($0=IN1,$1=IN2,$2=OUT,$3=VDD,$4=VSS);
+  subcircuit NAND $1 ($0=IN1,$1=IN2,$2=INT,$3=VDD,$4=VSS);
+  subcircuit NAND $2 ($0=IN1,$1=INT,$2=OUT,$3=VDD,$4=VSS);
+end;
+END
+
+    nls2 = <<"END"
+circuit NAND ($0=A,$1=B,$2=OUT,$3=VDD,$4=VSS);
+  device PMOS $1 (S=VDD,G=A,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device PMOS $2 (S=VDD,G=B,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $3 (S=VSS,G=A,D=INT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+  device NMOS $4 (S=INT,G=B,D=OUT) (L=0.25,W=0.95,AS=0.49875,AD=0.26125,PS=2.95,PD=1.5);
+end;
+circuit TOP ($0=IN1,$1=IN2,$2=OUT,$3=VDD,$4=VSS);
+  subcircuit NAND $2 ($0=IN1,$1=INT,$2=OUT,$3=VDD,$4=VSS);
+  subcircuit NAND $1 ($0=IN1,$1=IN2,$2=INT,$3=VDD,$4=VSS);
+end;
+END
+
+    nl1 = RBA::Netlist::new
+    nl2 = RBA::Netlist::new
+    prep_nl(nl1, nls1)
+    prep_nl(nl2, nls2)
+
+    logger = NetlistCompareTestLogger::new
+    comp = RBA::NetlistComparer::new(logger)
+
+    comp.equivalent_pins(nl2.circuit_by_name("NAND"), 0, 1)
+
+    good = comp.compare(nl1, nl2)
+
+    assert_equal(logger.text, <<"END")
+begin_circuit NAND NAND
+match_nets VSS VSS
+match_nets VDD VDD
+match_nets B B
+match_nets OUT OUT
+match_nets A A
+match_nets INT INT
+match_pins $0 $0
+match_pins $1 $1
+match_pins $2 $2
+match_pins $3 $3
+match_pins $4 $4
+match_devices $1 $1
+match_devices $2 $2
+match_devices $3 $3
+match_devices $4 $4
+end_circuit NAND NAND MATCH
+begin_circuit TOP TOP
+match_nets OUT OUT
+match_nets VSS VSS
+match_nets VDD VDD
+match_nets IN1 IN1
+match_nets INT INT
+match_nets IN2 IN2
+match_pins $0 $0
+match_pins $1 $1
+match_pins $2 $2
+match_pins $3 $3
+match_pins $4 $4
+match_subcircuits $2 $1
+match_subcircuits $1 $2
+end_circuit TOP TOP MATCH
+END
+
+    assert_equal(good, true)
+
+  end
+
+end
+
+load("test_epilogue.rb")
+