diff --git a/mocha.opts b/mocha.opts
index c70db2fd..4cd00237 100644
--- a/mocha.opts
+++ b/mocha.opts
@@ -1,4 +1,5 @@
 --require ts-node/register
+--require source-map-support/register
 --recursive
 --timeout=1000
 src/test/**/*.{ts,js}
diff --git a/package.json b/package.json
index 696be29c..1f67ddc2 100644
--- a/package.json
+++ b/package.json
@@ -49,6 +49,18 @@
     "url": "https://github.com/firebase/firebase-tools/issues"
   },
   "homepage": "https://github.com/firebase/firebase-tools",
+  "nyc": {
+    "require": [
+      "ts-node/register"
+    ],
+    "extension": [
+      ".js",
+      ".ts"
+    ],
+    "exclude": [
+      "src/test/**/*"
+    ]
+  },
   "dependencies": {
     "JSONStream": "^1.2.1",
     "archiver": "^2.1.1",
@@ -110,6 +122,7 @@
     "prettier": "1.14.3",
     "sinon": "^6.3.4",
     "sinon-chai": "^3.2.0",
+    "source-map-support": "^0.5.9",
     "ts-node": "^7.0.1",
     "tslint": "^5.11.0",
     "tslint-plugin-prettier": "^2.0.0",
diff --git a/src/fsutils.js b/src/fsutils.js
deleted file mode 100644
index 0a25628c..00000000
--- a/src/fsutils.js
+++ /dev/null
@@ -1,22 +0,0 @@
-"use strict";
-
-var fs = require("fs");
-
-module.exports = {
-  fileExistsSync: function(path) {
-    try {
-      var stats = fs.statSync(path);
-      return stats.isFile();
-    } catch (e) {
-      return false;
-    }
-  },
-  dirExistsSync: function(path) {
-    try {
-      var stats = fs.statSync(path);
-      return stats.isDirectory();
-    } catch (e) {
-      return false;
-    }
-  },
-};
diff --git a/src/fsutils.ts b/src/fsutils.ts
new file mode 100644
index 00000000..98300331
--- /dev/null
+++ b/src/fsutils.ts
@@ -0,0 +1,17 @@
+import { statSync } from "fs";
+
+export function fileExistsSync(path: string): boolean {
+  try {
+    return statSync(path).isFile();
+  } catch (e) {
+    return false;
+  }
+}
+
+export function dirExistsSync(path: string): boolean {
+  try {
+    return statSync(path).isDirectory();
+  } catch (e) {
+    return false;
+  }
+}
diff --git a/src/listFiles.ts b/src/listFiles.ts
index 2c6fd57b..3cf1f05e 100644
--- a/src/listFiles.ts
+++ b/src/listFiles.ts
@@ -1,11 +1,11 @@
-import * as glob from "glob";
+import { sync } from "glob";
 
-export function listFiles(cwd: string, ignore: string[]) {
-  return glob.sync("**/*", {
+export function listFiles(cwd: string, ignore: string[] = []): string[] {
+  return sync("**/*", {
     cwd,
     dot: true,
     follow: true,
-    ignore: ["**/firebase-debug.log", ".firebase/*"].concat(ignore || []),
+    ignore: ["**/firebase-debug.log", ".firebase/*"].concat(ignore),
     nodir: true,
     nosort: true,
   });
diff --git a/src/test/fsutils.spec.ts b/src/test/fsutils.spec.ts
new file mode 100644
index 00000000..3a7eddba
--- /dev/null
+++ b/src/test/fsutils.spec.ts
@@ -0,0 +1,33 @@
+import { expect } from "chai";
+
+import * as fsutils from "../fsutils";
+
+describe("fsutils", () => {
+  describe("fileExistsSync", () => {
+    it("should return true if the file exists", () => {
+      expect(fsutils.fileExistsSync(__filename)).to.be.true;
+    });
+
+    it("should return false if the file does not exist", () => {
+      expect(fsutils.fileExistsSync(`${__filename}/nope.never`)).to.be.false;
+    });
+
+    it("should return false if the path is a directory", () => {
+      expect(fsutils.fileExistsSync(__dirname)).to.be.false;
+    });
+  });
+
+  describe("dirExistsSync", () => {
+    it("should return true if the directory exists", () => {
+      expect(fsutils.dirExistsSync(__dirname)).to.be.true;
+    });
+
+    it("should return false if the directory does not exist", () => {
+      expect(fsutils.dirExistsSync(`${__dirname}/nope/never`)).to.be.false;
+    });
+
+    it("should return false if the path is a file", () => {
+      expect(fsutils.dirExistsSync(__filename)).to.be.false;
+    });
+  });
+});
diff --git a/src/test/listFiles.spec.ts b/src/test/listFiles.spec.ts
index 950b3bb3..af1fbd0c 100644
--- a/src/test/listFiles.spec.ts
+++ b/src/test/listFiles.spec.ts
@@ -1,13 +1,12 @@
 import { expect } from "chai";
-
-import * as path from "path";
+import { resolve } from "path";
 
 import { listFiles } from "../listFiles";
 
 describe("listFiles", () => {
   // for details, see the file structure and firebase.json in test/fixtures/ignores
   it("should ignore firebase-debug.log, specified ignores, and nothing else", () => {
-    const fileNames = listFiles(path.resolve(__dirname, "./fixtures/ignores"), [
+    const fileNames = listFiles(resolve(__dirname, "./fixtures/ignores"), [
       "**/.*",
       "firebase.json",
       "ignored.txt",
@@ -15,4 +14,18 @@ describe("listFiles", () => {
     ]);
     expect(fileNames).to.deep.equal(["index.html", "ignored/index.html", "present/index.html"]);
   });
+
+  it("should allow us to not specify additional ignores", () => {
+    const fileNames = listFiles(resolve(__dirname, "./fixtures/ignores"));
+    expect(fileNames.sort()).to.have.members([
+      ".hiddenfile",
+      "firebase.json",
+      "ignored.txt",
+      "ignored/deeper/index.txt",
+      "ignored/ignore.txt",
+      "ignored/index.html",
+      "index.html",
+      "present/index.html",
+    ]);
+  });
 });