diff --git a/source/Stargate-Model-Tests/HTTPNotAcceptableTest.extension.st b/source/Stargate-Model-Tests/HTTPNotAcceptableTest.extension.st
deleted file mode 100644
index 91f1790..0000000
--- a/source/Stargate-Model-Tests/HTTPNotAcceptableTest.extension.st
+++ /dev/null
@@ -1,16 +0,0 @@
-Extension { #name : #HTTPNotAcceptableTest }
-
-{ #category : #'*Stargate-Model-Tests' }
-HTTPNotAcceptableTest >> testNotAcceptableAsJSON [
-
-	| error json |
-
-	error := HTTPNotAcceptable messageText: 'Ouch!' accepting: {'application/xml' asMediaType}.
-	json := NeoJSONObject fromString: (NeoJSONWriter toStringPretty: error).
-
-	self
-		assert: json message equals: 'Ouch!';
-		assert: json code equals: 406;
-		assert: json allowedMediaTypes size equals: 1;
-		assert: json allowedMediaTypes first equals: 'application/xml'
-]
diff --git a/source/Stargate-Model-Tests/HyperspaceExtensionsTest.class.st b/source/Stargate-Model-Tests/HyperspaceExtensionsTest.class.st
new file mode 100644
index 0000000..cd5d634
--- /dev/null
+++ b/source/Stargate-Model-Tests/HyperspaceExtensionsTest.class.st
@@ -0,0 +1,33 @@
+Class {
+	#name : #HyperspaceExtensionsTest,
+	#superclass : #TestCase,
+	#category : #'Stargate-Model-Tests-Extensions'
+}
+
+{ #category : #tests }
+HyperspaceExtensionsTest >> testBadRequestAsJSON [
+
+	| error json |
+
+	error := HTTPClientError badRequest messageText: 'Ouch!'.
+	json := NeoJSONObject fromString: ( NeoJSONWriter toStringPretty: error ).
+
+	self
+		assert: json message equals: 'Ouch!';
+		assert: json code equals: 400
+]
+
+{ #category : #tests }
+HyperspaceExtensionsTest >> testNotAcceptableAsJSON [
+
+	| error json |
+
+	error := HTTPNotAcceptable messageText: 'Ouch!' accepting: {'application/xml' asMediaType}.
+	json := NeoJSONObject fromString: ( NeoJSONWriter toStringPretty: error ).
+
+	self
+		assert: json message equals: 'Ouch!';
+		assert: json code equals: 406;
+		assert: json allowedMediaTypes size equals: 1;
+		assert: json allowedMediaTypes first equals: 'application/xml'
+]