diff --git a/__tests__/util/bitArray.test.js b/__tests__/util/bitArray.test.js
new file mode 100644
index 00000000..d5ffffba
--- /dev/null
+++ b/__tests__/util/bitArray.test.js
@@ -0,0 +1,137 @@
+// jshint esversion: 6
+
+const BitArray = require("../../src/util/typedCrossfilter/bitArray");
+const defaultTestLength = 8;
+
+describe("default select state", () => {
+  test("newly created Bitarray should be deselected", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    const dim = ba.allocDimension();
+    expect(dim).toBeDefined();
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.freeDimension(dim);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+  });
+});
+
+describe("select and deselect", () => {
+  test("selectAll and deselectAll", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+    const dim1 = ba.allocDimension();
+    expect(dim1).toBeDefined();
+    ba.selectAll(dim1);
+
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+
+    const dim2 = ba.allocDimension();
+    expect(dim2).toBeDefined();
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.selectAll(dim2);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+
+    ba.deselectAll(dim1);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.deselectAll(dim2);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.selectAll(dim1);
+    ba.selectAll(dim2);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+
+    ba.freeDimension(dim1);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+
+    ba.freeDimension(dim2);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+  });
+
+  test("selectOne and deselectOne", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+    const dim = ba.allocDimension();
+    expect(dim).toBeDefined();
+
+    ba.selectOne(dim, 0);
+    expect(ba.isSelected(0)).toEqual(true);
+    for (let i = 1; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.deselectOne(dim, 0);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.selectOne(dim, 1);
+    expect(ba.isSelected(1)).toEqual(true);
+    expect(ba.isSelected(0)).toEqual(false);
+    for (let i = 2; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.selectAll(dim);
+    console.log(ba);
+    console.log(defaultTestLength - 1);
+    ba.deselectOne(dim, defaultTestLength - 1);
+    console.log(ba);
+    expect(ba.isSelected(defaultTestLength - 1)).toEqual(false);
+    for (let i = 0; i < defaultTestLength - 1; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+  });
+});
+
+describe("selectionCount", () => {
+  test("simple", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+    const dim1 = ba.allocDimension();
+    expect(dim1).toBeDefined();
+    const dim2 = ba.allocDimension();
+    expect(dim2).toBeDefined();
+
+    expect(ba.selectionCount).toEqual(0);
+    ba.selectAll(dim1);
+    expect(ba.selectionCount).toEqual(0);
+    ba.selectAll(dim2);
+    expect(ba.selectionCount).toEqual(defaultTestLength);
+
+    for (let i = 0; i < defaultTestLength; i++) {
+      ba.deselectOne(dim1, i);
+      expect(ba.selectionCount).toEqual(defaultTestLength - i - 1);
+    }
+
+    ba.freeDimension(dim1);
+    ba.freeDimension(dim2);
+  });
+});
diff --git a/__tests__/util/positiveInterval.test.js b/__tests__/util/positiveInterval.test.js
new file mode 100644
index 00000000..81c44496
--- /dev/null
+++ b/__tests__/util/positiveInterval.test.js
@@ -0,0 +1,140 @@
+// jshint esversion: 6
+
+const PositiveIntervals = require("../../src/util/typedCrossfilter/positiveIntervals");
+
+describe("canonicalize", () => {
+  test("empty", () => {
+    expect(PositiveIntervals.canonicalize([])).toEqual([]);
+  });
+
+  test("simple, already correct", () => {
+    expect(PositiveIntervals.canonicalize([[0, 1]])).toEqual([[0, 1]]);
+    expect(PositiveIntervals.canonicalize([[0, 1], [2, 3]])).toEqual([
+      [0, 1],
+      [2, 3]
+    ]);
+  });
+
+  test("non-canonical, need to be canonicalized", () => {
+    expect(PositiveIntervals.canonicalize([[0, 1], [1, 2]])).toEqual([[0, 2]]);
+    expect(PositiveIntervals.canonicalize([[1, 2], [2, 3]])).toEqual([[1, 3]]);
+  });
+});
+
+describe("union", () => {
+  test("empty range", () => {
+    expect(PositiveIntervals.union([], [])).toEqual([]);
+    expect(PositiveIntervals.union([], [[1, 2]])).toEqual([[1, 2]]);
+    expect(PositiveIntervals.union([], [[1, 2], [3, 4]])).toEqual([
+      [1, 2],
+      [3, 4]
+    ]);
+    expect(PositiveIntervals.union([[3, 4]], [])).toEqual([[3, 4]]);
+    expect(PositiveIntervals.union([[1, 2], [3, 4]], [])).toEqual([
+      [1, 2],
+      [3, 4]
+    ]);
+    expect(PositiveIntervals.union([[3, 3]], [])).toEqual([[3, 3]]);
+    expect(PositiveIntervals.union([], [[3, 3]])).toEqual([[3, 3]]);
+  });
+
+  test("simple ranges", () => {
+    expect(PositiveIntervals.union([[1, 2]], [[2, 3]])).toEqual([[1, 3]]);
+    expect(PositiveIntervals.union([[2, 3]], [[1, 2]])).toEqual([[1, 3]]);
+    expect(PositiveIntervals.union([[1, 2]], [[3, 4]])).toEqual([
+      [1, 2],
+      [3, 4]
+    ]);
+    expect(
+      PositiveIntervals.union([[1, 2], [3, 4]], [[6, 7], [19, 40]])
+    ).toEqual([[1, 2], [3, 4], [6, 7], [19, 40]]);
+    expect(PositiveIntervals.union([[1, 4]], [[1, 1], [3, 4]])).toEqual([
+      [1, 4]
+    ]);
+    expect(PositiveIntervals.union([[3, 3]], [[4, 4]])).toEqual([
+      [3, 3],
+      [4, 4]
+    ]);
+  });
+});
+
+describe("intersection", () => {
+  test("empty range", () => {
+    expect(PositiveIntervals.intersection([], [])).toEqual([]);
+    expect(PositiveIntervals.intersection([], [[1, 2]])).toEqual([]);
+    expect(PositiveIntervals.intersection([[1, 2]], [])).toEqual([]);
+  });
+
+  test("simple", () => {
+    expect(PositiveIntervals.intersection([[1, 2]], [[2, 3]])).toEqual([]);
+    expect(PositiveIntervals.intersection([[2, 3]], [[1, 2]])).toEqual([]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[1, 10]])).toEqual([
+      [1, 10]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[2, 8]])).toEqual([
+      [2, 8]
+    ]);
+    expect(PositiveIntervals.intersection([[2, 8]], [[1, 10]])).toEqual([
+      [2, 8]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[2, 12]])).toEqual([
+      [2, 10]
+    ]);
+    expect(PositiveIntervals.intersection([[2, 12]], [[1, 10]])).toEqual([
+      [2, 10]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[1, 8]])).toEqual([
+      [1, 8]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 8]], [[1, 10]])).toEqual([
+      [1, 8]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[1, 2], [6, 9]])).toEqual(
+      [[1, 2], [6, 9]]
+    );
+    expect(PositiveIntervals.intersection([[0, 2638]], [[1363, 2638]])).toEqual(
+      [[1363, 2638]]
+    );
+    expect(PositiveIntervals.intersection([[1, 2]], [[1, 2]])).toEqual([
+      [1, 2]
+    ]);
+  });
+});
+
+describe("difference", () => {
+  test("empty", () => {
+    expect(PositiveIntervals.difference([], [])).toEqual([]);
+    expect(PositiveIntervals.difference([], [[1, 10]])).toEqual([]);
+    expect(PositiveIntervals.difference([[1, 10]], [])).toEqual([[1, 10]]);
+  });
+
+  test("simple", () => {
+    expect(PositiveIntervals.difference([[1, 2], [3, 4]], [])).toEqual([
+      [1, 2],
+      [3, 4]
+    ]);
+    expect(PositiveIntervals.difference([[1, 2], [3, 10]], [[5, 10]])).toEqual([
+      [1, 2],
+      [3, 5]
+    ]);
+    expect(PositiveIntervals.difference([[1, 2], [3, 10]], [[0, 5]])).toEqual([
+      [5, 10]
+    ]);
+    expect(
+      PositiveIntervals.difference([[0, 2638]], [[0, 1363], [2055, 2638]])
+    ).toEqual([[1363, 2055]]);
+    expect(
+      PositiveIntervals.difference([[0, 1363], [2055, 2638]], [[0, 2638]])
+    ).toEqual([]);
+    expect(PositiveIntervals.difference([[0, 10]], [[0, 1]])).toEqual([
+      [1, 10]
+    ]);
+    expect(PositiveIntervals.difference([[0, 10]], [[1, 2]])).toEqual([
+      [0, 1],
+      [2, 10]
+    ]);
+    expect(PositiveIntervals.difference([[0, 10]], [[9, 10]])).toEqual([
+      [0, 9]
+    ]);
+  });
+});
diff --git a/package.json b/package.json
index 03568a9c..0698a3cb 100644
--- a/package.json
+++ b/package.json
@@ -4,12 +4,15 @@
   "license": "MIT",
   "repository": "https://github.com/chanzuckerberg/cellxgene",
   "scripts": {
-    "build": "npm run clean && webpack --config configuration/webpack/webpack.config.prod.js",
-    "dev": "npm run clean && webpack --config configuration/webpack/webpack.config.dev.js",
+    "build":
+      "npm run clean && webpack --config configuration/webpack/webpack.config.prod.js",
+    "dev":
+      "npm run clean && webpack --config configuration/webpack/webpack.config.dev.js",
     "clean": "rimraf build",
     "start": "node server/development.js",
     "lint": "eslint src",
-    "prod": "cross-env NODE_ENV=production PORT=3000 node server/production.js"
+    "prod": "cross-env NODE_ENV=production PORT=3000 node server/production.js",
+    "test": "jest"
   },
   "engineStrict": true,
   "engines": {
@@ -90,6 +93,7 @@
     "gzip-size": "^3.0.0",
     "html-webpack-inline-source-plugin": "0.0.6",
     "html-webpack-plugin": "^2.22.0",
+    "jest": "^23.0.1",
     "jsdom": "^9.4.1",
     "json-loader": "^0.5.4",
     "nyc": "^10.0.0",
@@ -106,5 +110,8 @@
     "webpack-dev-middleware": "^1.6.1",
     "webpack-hot-middleware": "^2.12.2",
     "whatwg-fetch": "^2.0.1"
+  },
+  "jest": {
+    "testMatch": ["**/__tests__/**/?(*.)(spec|test).js?(x)"]
   }
 }