From e2ffa0a34c4aebf17925884c5a3939d8d01ae836 Mon Sep 17 00:00:00 2001
From: yt-ms <71541861+yt-ms@users.noreply.github.com>
Date: Mon, 2 Nov 2020 09:41:58 +0000
Subject: [PATCH 1/2] fix(ModelItem): better error message on bogus constructor
 param

---
 CHANGELOG.rst                       |  1 +
 src/structurizr/model/model_item.py | 12 +++++++++++-
 tests/unit/model/test_model_item.py | 19 +++++++++++++++++++
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index a438020b..13e1a666 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -5,6 +5,7 @@ History
 Next Release
 ------------
 * Feat: Add implied relationships to entities (#42)
+* Fix: Better error on bad ModelItem constructor argument (#50)
 
 0.1.1 (2020-10-19)
 ------------------
diff --git a/src/structurizr/model/model_item.py b/src/structurizr/model/model_item.py
index 4e79ca25..7a61a460 100644
--- a/src/structurizr/model/model_item.py
+++ b/src/structurizr/model/model_item.py
@@ -83,7 +83,17 @@ def __init__(
         **kwargs,
     ):
         """"""
-        super().__init__(**kwargs)
+        if len(kwargs) > 0:
+            type_name = type(self).__name__
+            args = [f"'{key}'" for key in kwargs.keys()]
+            if len(args) == 1:
+                raise TypeError(f"{type_name}.__init__() got an unexpected "
+                                f"keyword argument {args[0]}")
+            else:
+                raise TypeError(f"{type_name}.__init__() got unexpected "
+                                f"keyword arguments {', '.join(args)}")
+
+        super().__init__()
         self.id = id
         self.tags = OrderedSet(tags)
         self.properties = dict(properties)
diff --git a/tests/unit/model/test_model_item.py b/tests/unit/model/test_model_item.py
index 496f9d86..6015bd1c 100644
--- a/tests/unit/model/test_model_item.py
+++ b/tests/unit/model/test_model_item.py
@@ -45,6 +45,25 @@ def test_model_item_init(attributes):
         assert getattr(model_item, attr) == expected
 
 
+def test_handling_of_bogus_init_params():
+    """
+    Test for sensible error message if wrong param passed.
+
+    See https://github.com/Midnighter/structurizr-python/issues/50.
+    """
+    with pytest.raises(
+        TypeError, match=r"ConcreteModelItem.__init__\(\) got an unexpected "
+                         r"keyword argument 'foo'"
+    ):
+        ConcreteModelItem(foo=7)
+    with pytest.raises(
+        TypeError,
+        match=r"ConcreteModelItem.__init__\(\) got unexpected keyword "
+              r"arguments 'foo', 'bar'",
+    ):
+        ConcreteModelItem(foo=7, bar=17)
+
+
 def test_default_element_tags_order(empty_model: Model):
     """
     Test that the default tags get added in the right order.

From ef4b95171dc4140d842ba3adfe195b6c816bd86f Mon Sep 17 00:00:00 2001
From: yt-ms <71541861+yt-ms@users.noreply.github.com>
Date: Mon, 2 Nov 2020 09:59:58 +0000
Subject: [PATCH 2/2] style: black reformatting

---
 src/structurizr/model/model_item.py | 12 ++++++++----
 tests/unit/model/test_model_item.py |  7 ++++---
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/src/structurizr/model/model_item.py b/src/structurizr/model/model_item.py
index 7a61a460..8f97b895 100644
--- a/src/structurizr/model/model_item.py
+++ b/src/structurizr/model/model_item.py
@@ -87,11 +87,15 @@ def __init__(
             type_name = type(self).__name__
             args = [f"'{key}'" for key in kwargs.keys()]
             if len(args) == 1:
-                raise TypeError(f"{type_name}.__init__() got an unexpected "
-                                f"keyword argument {args[0]}")
+                raise TypeError(
+                    f"{type_name}.__init__() got an unexpected "
+                    f"keyword argument {args[0]}"
+                )
             else:
-                raise TypeError(f"{type_name}.__init__() got unexpected "
-                                f"keyword arguments {', '.join(args)}")
+                raise TypeError(
+                    f"{type_name}.__init__() got unexpected "
+                    f"keyword arguments {', '.join(args)}"
+                )
 
         super().__init__()
         self.id = id
diff --git a/tests/unit/model/test_model_item.py b/tests/unit/model/test_model_item.py
index 6015bd1c..12a1d5b5 100644
--- a/tests/unit/model/test_model_item.py
+++ b/tests/unit/model/test_model_item.py
@@ -52,14 +52,15 @@ def test_handling_of_bogus_init_params():
     See https://github.com/Midnighter/structurizr-python/issues/50.
     """
     with pytest.raises(
-        TypeError, match=r"ConcreteModelItem.__init__\(\) got an unexpected "
-                         r"keyword argument 'foo'"
+        TypeError,
+        match=r"ConcreteModelItem.__init__\(\) got an unexpected "
+        r"keyword argument 'foo'",
     ):
         ConcreteModelItem(foo=7)
     with pytest.raises(
         TypeError,
         match=r"ConcreteModelItem.__init__\(\) got unexpected keyword "
-              r"arguments 'foo', 'bar'",
+        r"arguments 'foo', 'bar'",
     ):
         ConcreteModelItem(foo=7, bar=17)