diff --git a/repository/BaselineOfGrease.package/.filetree b/repository/BaselineOfGrease.package/.filetree
index 8998102c..57a67973 100644
--- a/repository/BaselineOfGrease.package/.filetree
+++ b/repository/BaselineOfGrease.package/.filetree
@@ -1,4 +1,5 @@
 {
-	"noMethodMetaData" : true,
 	"separateMethodMetaAndSource" : false,
-	"useCypressPropertiesFile" : true }
+	"noMethodMetaData" : true,
+	"useCypressPropertiesFile" : true
+}
\ No newline at end of file
diff --git a/repository/BaselineOfGrease.package/BaselineOfGrease.class/instance/baselineSqueak..st b/repository/BaselineOfGrease.package/BaselineOfGrease.class/instance/baselineSqueak..st
index e93226b5..2e742705 100644
--- a/repository/BaselineOfGrease.package/BaselineOfGrease.class/instance/baselineSqueak..st
+++ b/repository/BaselineOfGrease.package/BaselineOfGrease.class/instance/baselineSqueak..st
@@ -22,14 +22,7 @@ baselineSqueak: spec
 				package: 'Grease-Tests-Squeak-Core'
 					with: [ spec requires: #('Grease-Tests-Core') ];
 				package: 'Grease-Tests-Squeak5-Core'
-					with: [ spec requires: #('Grease-Tests-Squeak-Core') ];
-				package: 'Grease-Slime'
-					with: [ spec requires: #('Refactoring-Core' 'Grease-Core') ];
-				package: 'Grease-Tests-Slime'
-					with: [ spec requires: #('Grease-Slime') ].
-			spec
-				group: 'Slime' with: #('Grease-Slime');
-				group: 'Slime Tests' with: #('Grease-Tests-Slime') ].
+					with: [ spec requires: #('Grease-Tests-Squeak-Core') ] ].
 	spec
 		for: #(#'squeak6.x')
 		do: [
@@ -52,11 +45,4 @@ baselineSqueak: spec
 				package: 'Grease-Tests-Squeak-Core'
 					with: [ spec requires: #('Grease-Tests-Core') ];
 				package: 'Grease-Tests-Squeak6-Core'
-					with: [ spec requires: #('Grease-Tests-Squeak-Core') ];
-				package: 'Grease-Slime' 
-					with: [ spec requires: #('Refactoring-Core' 'Grease-Core') ];
-				package: 'Grease-Tests-Slime'
-					with: [ spec requires: #('Grease-Slime') ].
-			spec
-				group: 'Slime' with: #('Grease-Slime');
-				group: 'Slime Tests' with: #('Grease-Tests-Slime') ]
\ No newline at end of file
+					with: [ spec requires: #('Grease-Tests-Squeak-Core') ] ]
\ No newline at end of file
diff --git a/repository/BaselineOfGrease.package/BaselineOfGrease.class/properties.json b/repository/BaselineOfGrease.package/BaselineOfGrease.class/properties.json
index 8a39c621..0260395f 100644
--- a/repository/BaselineOfGrease.package/BaselineOfGrease.class/properties.json
+++ b/repository/BaselineOfGrease.package/BaselineOfGrease.class/properties.json
@@ -1,14 +1,11 @@
 {
-	"category" : "BaselineOfGrease",
-	"classinstvars" : [
-		 ],
-	"classvars" : [
-		 ],
 	"commentStamp" : "",
-	"instvars" : [
-		 ],
-	"name" : "BaselineOfGrease",
-	"pools" : [
-		 ],
 	"super" : "BaselineOf",
-	"type" : "normal" }
+	"category" : "BaselineOfGrease",
+	"classinstvars" : [ ],
+	"pools" : [ ],
+	"classvars" : [ ],
+	"instvars" : [ ],
+	"name" : "BaselineOfGrease",
+	"type" : "normal"
+}
\ No newline at end of file
diff --git a/repository/BaselineOfGrease.package/monticello.meta/categories.st b/repository/BaselineOfGrease.package/monticello.meta/categories.st
index 4a7c5b2b..95bd9e83 100644
--- a/repository/BaselineOfGrease.package/monticello.meta/categories.st
+++ b/repository/BaselineOfGrease.package/monticello.meta/categories.st
@@ -1,2 +1 @@
-SystemOrganization addCategory: #BaselineOfGrease!
-SystemOrganization addCategory: #'BaselineOfGrease-Manifest'!
+self packageOrganizer ensurePackage: #BaselineOfGrease withTags: #('Manifest')!
diff --git a/repository/BaselineOfGrease.package/properties.json b/repository/BaselineOfGrease.package/properties.json
index f037444a..6f31cf5a 100644
--- a/repository/BaselineOfGrease.package/properties.json
+++ b/repository/BaselineOfGrease.package/properties.json
@@ -1,2 +1 @@
-{
-	 }
+{ }
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/compile.in..st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/compile.in..st
index b03bce12..cb2577d5 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/compile.in..st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/compile.in..st
@@ -1,3 +1,7 @@
 accessing-code
 compile: aString in: aClass
-	^ aClass compile: aString classified: #(accessing)
\ No newline at end of file
+
+	GRPlatform current
+		compile: aString
+		into: aClass
+		classified: #accessing
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/defineClass.superclass..st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/defineClass.superclass..st
index 17204f23..9769e83e 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/defineClass.superclass..st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/defineClass.superclass..st
@@ -1,13 +1,4 @@
 accessing-code
 defineClass: aClassSymbol superclass: aSuperSymbol
-	| class |
-	model defineClass: aSuperSymbol , ' subclass: #' , aClassSymbol , '
-		instanceVariableNames: '''' 
-		classVariableNames: ''''
-		poolDictionaries: ''''
-		category: ''' , self category , ''''.
-	class := model classNamed: aClassSymbol.
-	environment 
-		addClass: class;
-		addClass: class theMetaClass.
-	^ class
\ No newline at end of file
+	"For compatibility"
+	^ self defineSubClassOf: aSuperSymbol
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/defineSubClassOf..st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/defineSubClassOf..st
new file mode 100644
index 00000000..4921f353
--- /dev/null
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/defineSubClassOf..st
@@ -0,0 +1,20 @@
+accessing-code
+defineSubClassOf: aSuperSymbol
+
+	| class |
+	class := SystemVersion current major >= 12
+		         ifTrue: [
+			         factory make: [ :aBuilder |
+				         aBuilder
+					         superclass: (Smalltalk at: aSuperSymbol);
+					         package: self category ] ]
+		         ifFalse: [
+			         factory
+				         newSubclassOf: (Smalltalk at: aSuperSymbol)
+				         instanceVariableNames: ''
+				         classVariableNames: 'classVarsString'
+				         category: self category ].
+	environment
+		addClass: class;
+		addClass: class theMetaClass.
+	^ class
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/setUp.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/setUp.st
index 0e7cc221..ee5004c0 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/setUp.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/setUp.st
@@ -1,5 +1,6 @@
 running
 setUp
 	super setUp.
+	factory := ClassFactoryForTestCase new.
 	model := RBNamespace new.
 	environment := RBClassEnvironment new
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/tearDown.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/tearDown.st
index f0cb9be4..82f6aabd 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/tearDown.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/tearDown.st
@@ -1,7 +1,5 @@
 running
 tearDown
+
 	super tearDown.
-	(Smalltalk organization listAtCategoryNamed: self category) do:[ :e | 
-		SmalltalkImage current removeClassNamed: e ].
-	Smalltalk organization
-		removeCategory: self category
\ No newline at end of file
+	factory cleanUp
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiBooleansRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiBooleansRule.st
index 7f500fce..d4560588 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiBooleansRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiBooleansRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testAnsiBooleansRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'and 1 and: [ 2 ] and: [ 3 ] and: [ 4 ]' in: class.
 	self compile: 'or 1 or: [ 2 ] or: [ 3 ] or: [ 4 ]' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiCharacterRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiCharacterRule.st
index 192f1f82..f8d58d84 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiCharacterRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiCharacterRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testAnsiCharacterRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'character Character value: 123' in: class.
 	self compile: 'characterRange $a to: $c' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiCollectionsRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiCollectionsRule.st
index 21f66b65..8b101581 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiCollectionsRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiCollectionsRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testAnsiCollectionsRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'withIndexDo #() withIndexDo: [ :each :index | each + index ]' in: class.
 	self compile: 'doWithIndex #() doWithIndex: [ :each :index | each + index ]' in: class.
 	self compile: 'collectThenDo #() collect: [ :a | a ] thenDo: [ :b | b ]' in: class.
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiConditionalsRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiConditionalsRule.st
index 0819b8e6..e1ac638b 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiConditionalsRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiConditionalsRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testAnsiConditionalsRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'ifNotNil 1 ifNotNil: [ | a | self or. self and ]' in: class.
 	self compile: 'ifNotNilDo 1 ifNotNilDo: [ :a | ^ a ]' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiConvertorRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiConvertorRule.st
index b51f8a3c..898f4f52 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiConvertorRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiConvertorRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testAnsiConvertorRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'convertInteger ''1'' asInteger' in: class.
 	self compile: 'convertString 2 asString' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiExceptionsRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiExceptionsRule.st
index 61cd5cd8..7232e149 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiExceptionsRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiExceptionsRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testAnsiExceptionsRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'exception1 [ self or ] on: Error do: [ self or ]' in: class.
 	self compile: 'exception2 [ self or ] on: Error do: [ self or. self or ]' in: class.
 	self compile: 'exception3 [ self or ] on: Error do: [ | a | a := 0 ]' in: class.
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiStreamsRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiStreamsRule.st
index d57fbb32..5f1430b1 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiStreamsRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiStreamsRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testAnsiStreamsRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'writeStream ^ '''' writeStream' in: class.
 	self compile: 'writeCr | stream | stream := WriteStream on: ''''. stream cr. stream nextPut: Character cr' in: class.
 	self compile: 'writeLf | stream | stream := WriteStream on: ''''. stream lf. stream nextPut: Character lf' in: class.
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiStringsRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiStringsRule.st
index 73f65771..dde1cae1 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiStringsRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testAnsiStringsRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testAnsiStringsRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'stringCr String cr, (String with: Character cr)' in: class.
 	self compile: 'stringTab String tab, (String with: Character tab)' in: class.
 	self compile: 'stringLf String lf, (String with: Character lf)' in: class.
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testBasicNewInitializeMissing.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testBasicNewInitializeMissing.st
index 137714dd..07bf2a45 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testBasicNewInitializeMissing.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testBasicNewInitializeMissing.st
@@ -1,9 +1,7 @@
 tests-block
 testBasicNewInitializeMissing
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #Object.
+	class := self defineSubClassOf: #Object.
 	self compile:  'initialize' in: class.
 	self
 		runRule: GRBasicNewInitializeMissingRule
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testBlockFormatting.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testBlockFormatting.st
index b29f187f..21cb487d 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testBlockFormatting.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testBlockFormatting.st
@@ -1,30 +1,28 @@
 tests-parsetree
 testBlockFormatting
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	class
+	class := self defineSubClassOf: #GRObject.
+	self 
 		compile: 'invalid1
 			[:a ]'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'invalid2
 			[:a | ]'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'invalid3
 			[ :b]'
-		classified: #(accessing).
+		in: class.
 	
-	class
+	self
 		compile: 'invalid4
 			[ :a| ]'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'invalid5
 			[ :a |a ]'
-		classified: #(accessing).
+		in: class.
 	self 
 		runRule: GRBlockFormattingRule
 		selectors: #(invalid1 invalid2 invalid3 invalid4 invalid5)
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testDeprecatedApiProtocol.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testDeprecatedApiProtocol.st
index 32f2b682..5735b56e 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testDeprecatedApiProtocol.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testDeprecatedApiProtocol.st
@@ -1,11 +1,9 @@
 tests-block
 testDeprecatedApiProtocol
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	self compile: 'deprecated1 self greaseDeprecatedApi: ''GRSlimeMockObject>>#deprecated1'' details: ''Something.''' in: class.
-	self compile: 'deprecated2 self greaseDeprecatedApi: ''GRSlimeMockObject>>#deprecated'' details: ''Something.''' in: class.
+	class := self defineSubClassOf: #GRObject.
+	self compile: 'deprecated1 self greaseDeprecatedApi: ''',class name,'>>#deprecated1'' details: ''Something.''' in: class.
+	self compile: 'deprecated2 self greaseDeprecatedApi: ''',class name,'>>#deprecated'' details: ''Something.''' in: class.
 	self compile: 'deprecated3 self greaseDeprecatedApi: ''GRSlimeMock>>#deprecated3'' details: ''Something.''' in: class.
 	self 
 		runRule: GRDeprecatedApiProtocolRule
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testEmptyStatements.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testEmptyStatements.st
index 2db3ea85..e4b03969 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testEmptyStatements.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testEmptyStatements.st
@@ -1,9 +1,7 @@
 tests-block
 testEmptyStatements
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'emptyStatement1. self and' in: class.
 	self compile: 'emptyStatement2 self and..' in: class.
 	self compile: 'emptyStatement3 self and."foo".' in: class.
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testInvalidObjectInitialization.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testInvalidObjectInitialization.st
index a3ad223e..f11fb191 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testInvalidObjectInitialization.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testInvalidObjectInitialization.st
@@ -1,9 +1,7 @@
 tests-block
 testInvalidObjectInitialization
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile:  'initializeFoo: aNumber' in: class.
 	self 
 		runRule: GRInvalidObjectInitializationRule
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNonPortableMessageRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNonPortableMessageRule.st
index 6deafde9..b9254341 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNonPortableMessageRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNonPortableMessageRule.st
@@ -1,9 +1,7 @@
 tests-block
 testNonPortableMessageRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 
 	self compile: 'invalid1 ^ Array new anyOne' in: class.
 	self compile: 'valid1 ^ Array new first' in: class.
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNonPortableSourceFormat.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNonPortableSourceFormat.st
index 7fd6ab30..cad8fe0b 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNonPortableSourceFormat.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNonPortableSourceFormat.st
@@ -1,9 +1,7 @@
 tests-block
 testNonPortableSourceFormat
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'invalid ^ ''Unicode snow man', (String with: (Character codePoint: 16r2603)) , '''' in: class.
 	self compile: 'valid ^ ''everything is fine''' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNotPortableCollectionsRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNotPortableCollectionsRule.st
index a0977f60..039b45c2 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNotPortableCollectionsRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testNotPortableCollectionsRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testNotPortableCollectionsRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'beginsWith1 ''abc'' beginsWith: ''a''' in: class.
 	self compile: 'endsWith1 ''abc'' endsWith: ''a''' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testObjectIn.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testObjectIn.st
index 7773b660..5aec1103 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testObjectIn.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testObjectIn.st
@@ -1,9 +1,7 @@
 tests-transform
 testObjectIn
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'objectIn1 1 in: [ :val | val factorial ]' in: class.
 	self compile: 'objectIn2 2 in: [ :val | | temps | val factorial ]' in: class.
 	self compile: 'objectIn3 2 in: [ ''not this'' ]' in: class.
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testParensFormatting.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testParensFormatting.st
index 4f64398f..a632b605 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testParensFormatting.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testParensFormatting.st
@@ -1,17 +1,15 @@
 tests-parsetree
 testParensFormatting
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	class
+	class := self defineSubClassOf: #GRObject.
+	self
 		compile: 'invalid1
 			( 1 + 2)'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'invalid2
 			(1 + 2 )'
-		classified: #(accessing).
+		in: class.
 	self 
 		runRule: GRParensFormattingRule
 		selectors: #(invalid1 invalid2)
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testReturnFormatting.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testReturnFormatting.st
index e9b3d738..27d8438d 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testReturnFormatting.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testReturnFormatting.st
@@ -1,17 +1,15 @@
 tests-parsetree
 testReturnFormatting
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	class
+	class := self defineSubClassOf: #GRObject.
+	self
 		compile: 'invalid1
 			^1'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'invalid2
 			^  2'
-		classified: #(accessing).
+		in: class.
 	self 
 		runRule: GRReturnFormattingRule
 		selectors: #(invalid1 invalid2)
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testTempsFormatting.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testTempsFormatting.st
index e8a4bb58..2eddb2b4 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testTempsFormatting.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testTempsFormatting.st
@@ -1,21 +1,19 @@
 tests-parsetree
 testTempsFormatting
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	class
+	class := self defineSubClassOf: #GRObject.
+	self
 		compile: 'invalid1
 			| a|'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'invalid2
 			|a |'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'invalid3
 			| a  b |'
-		classified: #(accessing).
+		in: class.
 	self 
 		runRule: GRTempsFormattingRule
 		selectors: #(invalid1 invalid2 invalid3)
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testTestCaseFailRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testTestCaseFailRule.st
index 987fa755..a4800822 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testTestCaseFailRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testTestCaseFailRule.st
@@ -1,9 +1,7 @@
 tests-transform
 testTestCaseFailRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObjectTest
-		superclass: #TestCase.
+	class := self defineSubClassOf: #TestCase.
 	self compile: 'testMethod self fail' in: class.
 	self 
 		runTransformation: GRTestAssertionsRule
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUnnecessaryLastPeriodRule.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUnnecessaryLastPeriodRule.st
index 71a76406..b96f1b62 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUnnecessaryLastPeriodRule.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUnnecessaryLastPeriodRule.st
@@ -1,9 +1,7 @@
 tests-block
 testUnnecessaryLastPeriodRule
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'invalid 1. 2.' in: class.
 	self compile: 'valid 1. 2' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesCanPerformOrUnderstand.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesCanPerformOrUnderstand.st
index 38c04498..a29a53fb 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesCanPerformOrUnderstand.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesCanPerformOrUnderstand.st
@@ -1,21 +1,19 @@
 tests-parsetree
 testUsesCanPerformOrUnderstand
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	class
+	class := self defineSubClassOf: #GRObject.
+	self
 		compile: 'invalid1
 			Object class canUnderstand: #new'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'invalid2
 			Object class canPerform: #new'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'valid
 			Object respondsTo: #new'
-		classified: #(accessing).
+		in: class.
 	self 
 		runRule: GRUsesCanPerformOrUnderstandRule
 		selectors: #(invalid1 invalid2)
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesClassForHash.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesClassForHash.st
index d61b8eb0..e95c920c 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesClassForHash.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesClassForHash.st
@@ -1,17 +1,15 @@
 tests-parsetree
 testUsesClassForHash
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	class
+	class := self defineSubClassOf: #GRObject.
+	self
 		compile: 'foo
 			^ super hash bitXor: self class hash'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'hash
 			^ super hash bitXor: self class hash'
-		classified: #(accessing).
+		in: class.
 	self 
 		runRule: GRUsesClassForHashRule
 		selectors: #(hash)
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesCurlyBraceArrays.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesCurlyBraceArrays.st
index 61084706..7e341c1e 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesCurlyBraceArrays.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesCurlyBraceArrays.st
@@ -3,17 +3,15 @@ testUsesCurlyBraceArrays
 	| class |
 	(self canParse: 'foo { self foo. self bar }')
 		ifFalse: [ ^ self ].
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	class
+	class := self defineSubClassOf: #GRObject.
+	self
 		compile: 'invalid
 			^ { self foo. self bar }'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'valid
 			^ Array new'
-		classified: #(accessing).
+		in: class.
 	self 
 		runRule: GRUsesCurlyBraceArraysRule
 		selectors: #(invalid)
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesLiteralByteArrays.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesLiteralByteArrays.st
index 556f4d77..342eb995 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesLiteralByteArrays.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesLiteralByteArrays.st
@@ -3,17 +3,15 @@ testUsesLiteralByteArrays
 	| class |
 	(self canParse: 'foo #[ 1 2 3 ]')
 		ifFalse: [ ^ self ].
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
-	class
+	class := self defineSubClassOf: #GRObject.
+	self
 		compile: 'invalid
 			^ #[ 1 2 3 ]'
-		classified: #(accessing).
-	class
+		in: class.
+	self
 		compile: 'valid
 			^ ByteArray with: 1 with: 2 with: 3'
-		classified: #(accessing).
+		in: class.
 	self 
 		runRule: GRUsesLiteralByteArraysRule
 		selectors: #(invalid)
\ No newline at end of file
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesMethodAnnotations.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesMethodAnnotations.st
index 39519d9b..dd1e7931 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesMethodAnnotations.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesMethodAnnotations.st
@@ -3,9 +3,7 @@ testUsesMethodAnnotations
 	| class |
 	(self canParse: 'foo <foo: 123>')
 		ifFalse: [ ^ self ].
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'invalid <foo: 123>' in: class.
 	self compile: 'valid' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesNotPortableClass.st b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesNotPortableClass.st
index a4945bb4..d988a2fd 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesNotPortableClass.st
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/instance/testUsesNotPortableClass.st
@@ -1,9 +1,7 @@
 tests-block
 testUsesNotPortableClass
 	| class |
-	class := self
-		defineClass: #GRSlimeMockObject
-		superclass: #GRObject.
+	class := self defineSubClassOf: #GRObject.
 	self compile: 'invalid ^ Semaphore new' in: class.
 	self compile: 'valid ^ GRObject new' in: class.
 	self 
diff --git a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/properties.json b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/properties.json
index e01b8a06..b2e89aff 100644
--- a/repository/Grease-Tests-Slime.package/GRSlimeTest.class/properties.json
+++ b/repository/Grease-Tests-Slime.package/GRSlimeTest.class/properties.json
@@ -7,7 +7,8 @@
 	"classvars" : [ ],
 	"instvars" : [
 		"model",
-		"environment"
+		"environment",
+		"factory"
 	],
 	"name" : "GRSlimeTest",
 	"type" : "normal"
diff --git a/repository/Grease-Tests-Slime.package/monticello.meta/categories.st b/repository/Grease-Tests-Slime.package/monticello.meta/categories.st
index d34cfb4a..a49916c2 100644
--- a/repository/Grease-Tests-Slime.package/monticello.meta/categories.st
+++ b/repository/Grease-Tests-Slime.package/monticello.meta/categories.st
@@ -1 +1 @@
-SystemOrganization addCategory: #'Grease-Tests-Slime'!
+self packageOrganizer ensurePackage: #'Grease-Tests-Slime' withTags: #()!