ID3Tests.cs

using System.Collections.Generic;
using AlgorithmsAndDataStructures.DataStructures.DecisionTree;
using Xunit;

namespace AlgorithmsAndDataStructures.Tests.DataStructures.DecisionTree;

public class Id3Tests
{
    [Fact]
    public void Base()
    {
        var sut = new Id3();

        var example1 = new Dictionary<string, string>
        {
            { "outlook", "sunny" },
            { "humidity", "high" },
            { "windy", "false" },
            { "class", "N" }
        };
        var example2 = new Dictionary<string, string>
        {
            { "outlook", "overcast" },
            { "humidity", "high" },
            { "windy", "false" },
            { "class", "P" }
        };
        var example3 = new Dictionary<string, string>
        {
            { "outlook", "rain" },
            { "humidity", "high" },
            { "windy", "false" },
            { "class", "P" }
        };
        var example4 = new Dictionary<string, string>
        {
            { "outlook", "sunny" },
            { "humidity", "normal" },
            { "windy", "false" },
            { "class", "P" }
        };
        var example5 = new Dictionary<string, string>
        {
            { "outlook", "rain" },
            { "humidity", "high" },
            { "windy", "true" },
            { "class", "N" }
        };
        var example6 = new Dictionary<string, string>
        {
            { "outlook", "rain" },
            { "humidity", "normal" },
            { "windy", "true" },
            { "class", "N" }
        };
        var examples = new[] { example1, example2, example3, example4, example5, example6 };
        var attributes = new Dictionary<string, List<string>>();
        attributes.Add("outlook", new List<string> { "sunny", "rain", "overcast" });
        attributes.Add("humidity", new List<string> { "high", "normal" });
        attributes.Add("windy", new List<string> { "true", "false" });

        var decisionTree = sut.CreateDecisionTree(examples, "class", attributes);

        Assert.Equal("windy", decisionTree.TestAttributeName);
        Assert.Equal("true", decisionTree.Children[0].BranchForValue);
        Assert.Equal("N", decisionTree.Children[0].TargetAttribute.Value);
        Assert.Equal("false", decisionTree.Children[1].BranchForValue);

        Assert.Equal("outlook", decisionTree.Children[1].TestAttributeName);
        Assert.Equal("sunny", decisionTree.Children[1].Children[0].BranchForValue);
        Assert.Equal("rain", decisionTree.Children[1].Children[1].BranchForValue);
        Assert.Equal("P", decisionTree.Children[1].Children[1].TargetAttribute.Value);
        Assert.Equal("overcast", decisionTree.Children[1].Children[2].BranchForValue);
    }
}