old_contents: function runGFFTests() {
  
      // mock object
  
      const genome = {
          getChromosomeName: function (chr) {
              return chr.startsWith("chr") ? chr : "chr" + chr;
          }
      }
  
      QUnit.test("GFF query", function(assert) {
  				var done = assert.async();
  
          var chr = "chr1",
              bpStart = 1,
              bpEnd = 10000,
              featureSource = new igv.FeatureSource({
                      url: 'data/gff/eden.gff',
                      format: 'gff3'
                  },
                  genome);
  
          featureSource.getFeatures(chr, bpStart, bpEnd).then(function (features) {
  
              assert.ok(features);
              assert.equal(5, features.length);
              assert.equal(chr, features[0].chr); // ensure features chromosome is specified chromosome
  
              done();
          })
              .catch(function (error) {
                  console.log(error);
                  assert.ok(false);
                  done();
              });
      });
  }
  
new_contents: function runGFFTests() {
  
      // mock object
  
      const genome = {
          getChromosomeName: function (chr) {
              return chr.startsWith("chr") ? chr : "chr" + chr;
          }
      }
  
      QUnit.test("GFF query", function(assert) {
  				var done = assert.async();
  
          var chr = "chr1",
              bpStart = 1,
              bpEnd = 10000,
              featureSource = new igv.FeatureSource({
                      url: 'data/gff/eden.gff',
                      format: 'gff3',
                      filterTypes: []
                  },
                  genome);
  
          featureSource.getFeatures(chr, bpStart, bpEnd).then(function (features) {
  
              assert.ok(features);
              assert.equal(5, features.length);
              assert.equal(chr, features[0].chr); // ensure features chromosome is specified chromosome
  
              done();
          })
              .catch(function (error) {
                  console.log(error);
                  assert.ok(false);
                  done();
              });
      });
  }
  
subject: fix unit test