diff --git a/exercises/practice/perfect-numbers/runtests.jl b/exercises/practice/perfect-numbers/runtests.jl
index 982d35a1..bed66da8 100644
--- a/exercises/practice/perfect-numbers/runtests.jl
+++ b/exercises/practice/perfect-numbers/runtests.jl
@@ -15,6 +15,11 @@ include("perfect-numbers.jl")
     @testset "Large perfect number is classified correctly" begin
         @test isperfect(33550336)
     end
+    
+    @testset "Correctly handles non-perfect numbers" begin
+        @test !isperfect(12)
+        @test !isperfect(4)
+    end
 end
 
 @testset "Abundant numbers" begin
@@ -30,6 +35,11 @@ end
     @testset "Large abundant number is classified correctly" begin
         @test isabundant(33550335)
     end
+
+    @testset "Correctly handles non-abundant numbers" begin
+        @test !isabundant(6)
+        @test !isabundant(32)
+    end
 end
 
 @testset "Deficient numbers" begin
@@ -53,6 +63,11 @@ end
     @testset "Edge case (no factors other than itself) is classified correctly" begin
         @test isdeficient(1)
     end
+
+    @testset "Correctly handles non-deficient numbers" begin
+        @test !isdeficient(28)
+        @test !isdeficient(30)
+    end
 end
 
 @testset "Invalid inputs" begin