From 2d5aadc79fb920e675a7b61c88ac13fb99af22a0 Mon Sep 17 00:00:00 2001
From: Seimen <seimen@cloasdata.de>
Date: Sat, 4 Jan 2025 09:35:17 +0100
Subject: [PATCH 1/3] type in docstring StreamArgs

---
 thermo/stream.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/thermo/stream.py b/thermo/stream.py
index f08e94df..dfd58ca2 100644
--- a/thermo/stream.py
+++ b/thermo/stream.py
@@ -71,11 +71,11 @@ class StreamArgs:
     Handling flow flow vs. composition is fuzzier because of the common use cases
     where a flow rate may be known, but not composition; or the composition but not
     the flow, however later when the product
-    flows are known it is desireable to set it. To allow this,
+    flows are known it is desirable to set it. To allow this,
     the variables `ns`, `ms`, `Qls`, and `Qgs` are allowed to overwrite an existing
     flow and/or composition specification even if if `multiple_composition_basis` is False.
 
-    Eveen if the property wasn't set to this object, but if enough degrees of freedom
+    Even if the property wasn't set to this object, but if enough degrees of freedom
     are known, the actual value can usually be queried by adding `_calc` to the attribute,
     e.g. `H_calc` is available if `T`, `P`, and `zs` are known. This will perform the
     flash if it hasn't already been done.

From d98137c044d09a88a40f3b07052679c0800ae22b Mon Sep 17 00:00:00 2001
From: Seimen <seimen@cloasdata.de>
Date: Mon, 6 Jan 2025 12:55:15 +0100
Subject: [PATCH 2/3] added failing test for stream.copy() method on a user
 child class in test_stream.py

---
 tests/test_stream.py | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/tests/test_stream.py b/tests/test_stream.py
index 4f5b1df3..5c4f2c41 100644
--- a/tests/test_stream.py
+++ b/tests/test_stream.py
@@ -247,7 +247,34 @@ def test_sub_streams():
     assert m.CASs == ['7732-18-5']
 
 
-
+@pytest.fixture(
+    params=[
+        (StreamArgs,{}),
+        (EnergyStream,dict(Q=0))
+    ],
+    ids="StreamArgs EnergyStream".split()
+)
+def any_type_of_stream(request):
+    return request.param
+
+def test_stream_copy(any_type_of_stream):
+    stream_type, param = any_type_of_stream
+    expected_args = stream_type(**param)
+    # when copied
+    stream_copy = expected_args.copy()
+    # then
+    assert isinstance(stream_copy, stream_type)
+
+def test_child_class_copy(any_type_of_stream):
+    # lets say user wants to enhance StreamArgs class by:
+    stream_type, param = any_type_of_stream
+    class EnhancedStreamArgs(stream_type):
+        pass
+    expected_args = EnhancedStreamArgs(**param)
+    # when copied
+    stream_copy = expected_args.copy()
+    # then
+    assert isinstance(stream_copy, EnhancedStreamArgs)
 
 
 def test_StreamArgs_flow_overspecified():

From 363a9a3e464790d4e7ebedc4716930d00749d2c6 Mon Sep 17 00:00:00 2001
From: Seimen <seimen@cloasdata.de>
Date: Mon, 6 Jan 2025 12:57:05 +0100
Subject: [PATCH 3/3] bugfix .copy on stream objects break lisp. Instead, we're
 using the class ctor by invoke self.__class__

This fix is necessary to copy the slotted class.
---
 thermo/stream.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/thermo/stream.py b/thermo/stream.py
index dfd58ca2..73be071b 100644
--- a/thermo/stream.py
+++ b/thermo/stream.py
@@ -382,7 +382,7 @@ def copy(self):
             kwargs['Vfgs'] = [i for i in kwargs['Vfgs']]
         if kwargs['Vfls'] is not None:
             kwargs['Vfls'] = [i for i in kwargs['Vfls']]
-        return StreamArgs(Vf_TP=self.Vf_TP, Q_TP=self.Q_TP, flasher=self.flasher,
+        return self.__class__(Vf_TP=self.Vf_TP, Q_TP=self.Q_TP, flasher=self.flasher,
                  multiple_composition_basis=self.multiple_composition_basis, **kwargs)
 
     __copy__ = copy
@@ -2996,7 +2996,7 @@ def copy(self):
         copy : EnergyStream
             Copied Energy Stream, [-]
         '''
-        return EnergyStream(Q=self.Q)
+        return self.__class__(Q=self.Q)
 
     __copy__ = copy