binary_search_tree

elixir/binary-search-tree/test/binary_search_tree_test.exs

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+defmodule BinarySearchTreeTest do
+  use ExUnit.Case
+
+  test "data is retained" do
+    root = BinarySearchTree.new(4)
+    assert root.data == 4
+    assert root.left == nil
+    assert root.right == nil
+  end
+
+  describe "insert data at proper node" do
+    test "smaller number at left node" do
+      root =
+        BinarySearchTree.new(4)
+        |> BinarySearchTree.insert(2)
+
+      assert root.data == 4
+      assert root.left.data == 2
+      assert root.left.left == nil
+      assert root.left.right == nil
+      assert root.right == nil
+    end
+
+    test "same number at left node" do
+      root =
+        BinarySearchTree.new(4)
+        |> BinarySearchTree.insert(4)
+
+      assert root.data == 4
+      assert root.left.data == 4
+      assert root.left.left == nil
+      assert root.left.right == nil
+      assert root.right == nil
+    end
+
+    test "greater number at right node" do
+      root =
+        BinarySearchTree.new(4)
+        |> BinarySearchTree.insert(5)
+
+      assert root.data == 4
+      assert root.left == nil
+      assert root.right.data == 5
+      assert root.right.left == nil
+      assert root.right.right == nil
+    end
+  end
+
+  test "can create complex tree" do
+    root =
+      BinarySearchTree.new(4)
+      |> BinarySearchTree.insert(2)
+      |> BinarySearchTree.insert(6)
+      |> BinarySearchTree.insert(1)
+      |> BinarySearchTree.insert(3)
+      |> BinarySearchTree.insert(5)
+      |> BinarySearchTree.insert(7)
+
+    assert root.data == 4
+    assert root.left.data == 2
+    assert root.left.left.data == 1
+    assert root.left.left.left == nil
+    assert root.left.left.right == nil
+    assert root.left.right.data == 3
+    assert root.left.right.left == nil
+    assert root.left.right.right == nil
+    assert root.right.data == 6
+    assert root.right.left.data == 5
+    assert root.right.left.left == nil
+    assert root.right.left.right == nil
+    assert root.right.right.data == 7
+    assert root.right.right.left == nil
+    assert root.right.right.right == nil
+  end
+
+  describe "can sort data" do
+    test "can sort single number" do
+      root = BinarySearchTree.new(2)
+
+      assert [2] == BinarySearchTree.in_order(root)
+    end
+
+    test "can sort if second number is smaller than first" do
+      root =
+        BinarySearchTree.new(2)
+        |> BinarySearchTree.insert(1)
+
+      assert [1, 2] == BinarySearchTree.in_order(root)
+    end
+
+    test "can sort if second number is the same as the first" do
+      root =
+        BinarySearchTree.new(2)
+        |> BinarySearchTree.insert(2)
+
+      assert [2, 2] == BinarySearchTree.in_order(root)
+    end
+
+    test "can sort if second number is greater than the first" do
+      root =
+        BinarySearchTree.new(2)
+        |> BinarySearchTree.insert(3)
+
+      assert [2, 3] == BinarySearchTree.in_order(root)
+    end
+
+    test "can sort complex tree" do
+      root =
+        BinarySearchTree.new(2)
+        |> BinarySearchTree.insert(1)
+        |> BinarySearchTree.insert(3)
+        |> BinarySearchTree.insert(6)
+        |> BinarySearchTree.insert(7)
+        |> BinarySearchTree.insert(5)
+
+      assert [1, 2, 3, 5, 6, 7] == BinarySearchTree.in_order(root)
+    end
+  end
+end

elixir/binary-search-tree/test/test_helper.exs

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