perfect-numbers

elixir/perfect-numbers/test/perfect_numbers_test.exs

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+defmodule PerfectNumbersTest do
+  use ExUnit.Case
+
+  describe "Perfect numbers" do
+    test "Smallest perfect number is classified correctly" do
+      assert PerfectNumbers.classify(6) == {:ok, :perfect}
+    end
+
+    test "Medium perfect number is classified correctly" do
+      assert PerfectNumbers.classify(28) == {:ok, :perfect}
+    end
+
+    test "Large perfect number is classified correctly" do
+      assert PerfectNumbers.classify(33_550_336) == {:ok, :perfect}
+    end
+  end
+
+  describe "Abundant numbers" do
+    test "Smallest abundant number is classified correctly" do
+      assert PerfectNumbers.classify(12) == {:ok, :abundant}
+    end
+
+    test "Medium abundant number is classified correctly" do
+      assert PerfectNumbers.classify(30) == {:ok, :abundant}
+    end
+
+    test "Large abundant number is classified correctly" do
+      assert PerfectNumbers.classify(33_550_335) == {:ok, :abundant}
+    end
+  end
+
+  describe "Deficient numbers" do
+    test "Smallest prime deficient number is classified correctly" do
+      assert PerfectNumbers.classify(2) == {:ok, :deficient}
+    end
+
+    test "Smallest non-prime deficient number is classified correctly" do
+      assert PerfectNumbers.classify(4) == {:ok, :deficient}
+    end
+
+    test "Medium deficient number is classified correctly" do
+      assert PerfectNumbers.classify(32) == {:ok, :deficient}
+    end
+
+    test "Large deficient number is classified correctly" do
+      assert PerfectNumbers.classify(33_550_337) == {:ok, :deficient}
+    end
+
+    test "Edge case (no factors other than itself) is classified correctly" do
+      assert PerfectNumbers.classify(1) == {:ok, :deficient}
+    end
+  end
+
+  describe "Invalid inputs" do
+    test "Zero is rejected (not a natural number)" do
+      assert PerfectNumbers.classify(0) ==
+               {:error, "Classification is only possible for natural numbers."}
+    end
+
+    test "Negative integer is rejected (not a natural number)" do
+      assert PerfectNumbers.classify(-1) ==
+               {:error, "Classification is only possible for natural numbers."}
+    end
+  end
+end

elixir/perfect-numbers/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true)