@__username/decision-tree/tst/validation.js

NodeJS implementation of decision tree using ID3 algorithm

var assert = require('assert');
var ID3 = require('lib/decision-tree');

describe('Decision Tree Validation', function() {
  describe('constructor', function() {
    describe('feature list', function() {
      it('should not be NULL', function() {
        assert.throws(function() {
          new ID3("a");
        });
      });

      it('should not be EMPTY', function() {
        assert.throws(function() {
          new ID3("a", []);
        });
      });

      it('should be list of strings', function() {
        assert.throws(function() {
          new ID3("a", ["b", 1]);
        });
      });
    });

    describe('target class', function() {
      it('should not be NULL', function() {
        assert.throws(function() {
          new ID3(null, ["b"]);
        });
      });

      it('should not be BLANK', function() {
        assert.throws(function() {
          new ID3(" ", ["b"]);
        });
      });

      it('should not be in feature list', function() {
        assert.throws(function() {
          new ID3("a", ["a", "b"]);
        });
      });
    });
  });

  describe('training', function() {
    describe('sample data-set', function() {
      var dt;
      beforeEach(function() {
        dt = new ID3("a", ["b"]);
      });

      it('should be a List<Map<String, Primitive>>', function() {
        assert.doesNotThrow(function() {
          dt.train([{a:1,b:'x',c:new Date,d:true}]);
        });

        assert.throws(function() {
          dt.train([{a:1,b:[1,2]},{a:3,b:1}]);
        });

        assert.throws(function() {
          dt.train([{a:1,b:{a:1,b:2}},{a:3,b:1}]);
        });
      });

      it('should not be missing the target-class', function() {
        assert.doesNotThrow(function() {
          dt.train([{a:1,b:"x",c:50}, {b:"y",c:10}]);
        });
      });

      it('should not have missing features', function() {
        assert.doesNotThrow(function() {
          new ID3("a", ["d"])
            .train([{a:1,b:"x",c:50}, {b:"y",c:10}]);
        });
      });
    });
  });

  describe('prediction', function() {
    describe('sample to predict on', function() {
      const SAMPLE_DATA_SET = require('data/sample.json');
      const SAMPLE_DATASET_CLASS_NAME = 'liked';

      it('should not contain untrained features', function() {
        assert.throws(function() {
          var dt = new ID3(SAMPLE_DATASET_CLASS_NAME, SAMPLE_DATA_SET.featureList)
          dt.train(SAMPLE_DATA_SET.data);
          dt.predict({ non_existent_feature: "non-existent feature" });
        });
      });

      it('should not contain feature with unseen values', function() {
        assert.throws(function() {
          var dt = new ID3(SAMPLE_DATASET_CLASS_NAME, SAMPLE_DATA_SET.featureList, { verbose: true });
          dt.train(SAMPLE_DATA_SET.data);
          dt.predict({ color: "green", shape: "square" });
        });
      });
    });
  });
});