hamming

elixir/hamming/test/hamming_test.exs

@@ -0,0 +1,41 @@
+defmodule HammingTest do
+  use ExUnit.Case
+
+  test "empty strands" do
+    assert Hamming.hamming_distance(~c"", ~c"") == {:ok, 0}
+  end
+
+  test "single letter identical strands" do
+    assert Hamming.hamming_distance(~c"A", ~c"A") == {:ok, 0}
+  end
+
+  test "single letter different strands" do
+    assert Hamming.hamming_distance(~c"G", ~c"T") == {:ok, 1}
+  end
+
+  test "long identical strands" do
+    assert Hamming.hamming_distance(~c"GGACTGAAATCTG", ~c"GGACTGAAATCTG") == {:ok, 0}
+  end
+
+  test "long different strands" do
+    assert Hamming.hamming_distance(~c"GGACGGATTCTG", ~c"AGGACGGATTCT") == {:ok, 9}
+  end
+
+  test "disallow first strand longer" do
+    assert {:error, "strands must be of equal length"} =
+             Hamming.hamming_distance(~c"AATG", ~c"AAA")
+  end
+
+  test "disallow second strand longer" do
+    assert {:error, "strands must be of equal length"} =
+             Hamming.hamming_distance(~c"ATA", ~c"AGTG")
+  end
+
+  test "disallow empty first strand" do
+    assert {:error, "strands must be of equal length"} = Hamming.hamming_distance(~c"", ~c"G")
+  end
+
+  test "disallow empty second strand" do
+    assert {:error, "strands must be of equal length"} = Hamming.hamming_distance(~c"G", ~c"")
+  end
+end

elixir/hamming/test/test_helper.exs

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