diff --git a/src/Z3-Tests/Z3DatatypeTest.class.st b/src/Z3-Tests/Z3DatatypeTest.class.st
new file mode 100644
index 000000000..6234b3489
--- /dev/null
+++ b/src/Z3-Tests/Z3DatatypeTest.class.st
@@ -0,0 +1,42 @@
+"
+These tests correspond to L8uniqueVoid.smt2 on our experiment-z3datatypes
+branch of liquid-fixpoint, see dbd390e:
+https://github.com/shingarov/liquid-fixpoint/commit/dbd390e323a96f5c973c5bd6285a10b066340b0b
+at the lowest (SMT) level of the test-ladder, cf:
+https://github.com/shingarov/sprite-lang/commit/248f59b7758befa7a812b1981b43999a8c45adb6
+
+"
+Class {
+	#name : #Z3DatatypeTest,
+	#superclass : #TestCase,
+	#category : #'Z3-Tests-ADT'
+}
+
+{ #category : #running }
+Z3DatatypeTest >> testUniqueVoid [
+	| V x y |
+	V := Z3Datatype named: 'V'.
+	V declare: 'Nil'.
+	V := V create.
+	x := V mkConst: 'x'.
+	y := V mkConst: 'y'.
+	self assert: (x===y) isValid
+]
+
+{ #category : #running }
+Z3DatatypeTest >> testUniqueVoidNeg [
+	| V x y solver model xConsName yConsName |
+	V := Z3Datatype named: 'V'.
+	V declare: 'One'.
+	V declare: 'Two'.
+	V := V create.
+	x := V mkConst: 'x'.
+	y := V mkConst: 'y'.
+	"exactly two counterexamples"
+	solver := Z3Solver new.
+	model := (solver findCounterexample: x===y) constants.
+	xConsName := (model at: 'x') functorName.
+	yConsName := (model at: 'y') functorName.
+	self assert: (xConsName='One' and: yConsName='Two')
+	           | (yConsName='One' and: xConsName='Two')
+]