diff --git a/tests/AlgebraTest.php b/tests/AlgebraTest.php
index 29e52fa164e..6571701c436 100644
--- a/tests/AlgebraTest.php
+++ b/tests/AlgebraTest.php
@@ -73,8 +73,8 @@ public function testNegateFormula(): void
         $negated_formula = Algebra::negateFormula($formula);
 
         $this->assertCount(3, $negated_formula);
-        $this->assertSame('$a is not string', (string)$negated_formula[0]);
-        $this->assertSame('$a is not int', (string)$negated_formula[1]);
+        $this->assertSame('$a is not int', (string)$negated_formula[0]);
+        $this->assertSame('$a is not string', (string)$negated_formula[1]);
         $this->assertSame('!$b', (string)$negated_formula[2]);
     }