diff --git a/.travis.yml b/.travis.yml
index 966d2dc08..0d36d96c2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,8 @@
 language: node_js
-node_js: "lts/*"
+node_js:
+    - "10"
+    - "8"
+    - "6"
 jobs:
   include:
     - stage: test
diff --git a/package.json b/package.json
index a7950875a..88f44179c 100644
--- a/package.json
+++ b/package.json
@@ -7,8 +7,8 @@
   "browser": "dist/liquid.js",
   "scripts": {
     "lint": "eslint . --ext .ts --ext .js",
-    "unit": "mocha test/unit/*.ts test/unit/**/*.ts",
-    "e2e": "npm run build && mocha test/e2e/**/*.ts test/e2e/*.ts",
+    "unit": "mocha 'test/unit/**/*.ts'",
+    "e2e": "npm run build && mocha 'test/e2e/**/*.ts'",
     "test": "npm run unit && npm run e2e",
     "coverage-html": "nyc npm run unit && nyc report --reporter=html",
     "coverage-coveralls": "nyc npm run unit && nyc report --reporter=text-lcov | coveralls",
diff --git a/test/unit/builtin/filters/array.ts b/test/unit/builtin/filters/array.ts
index 625060511..01e07b2f4 100644
--- a/test/unit/builtin/filters/array.ts
+++ b/test/unit/builtin/filters/array.ts
@@ -1,4 +1,4 @@
-import { test, ctx, liquid } from 'test/stub/render'
+import { test } from 'test/stub/render'
 
 describe('filters/array', function () {
   describe('join', function () {
diff --git a/test/unit/builtin/filters/date.ts b/test/unit/builtin/filters/date.ts
index 0fbd6638d..4f9324492 100644
--- a/test/unit/builtin/filters/date.ts
+++ b/test/unit/builtin/filters/date.ts
@@ -1,4 +1,4 @@
-import { test, ctx, liquid } from 'test/stub/render'
+import { test, ctx } from 'test/stub/render'
 
 describe('filters/date', function () {
   it('should support date: %a %b %d %Y', function () {
diff --git a/test/unit/builtin/filters/html.ts b/test/unit/builtin/filters/html.ts
index 846329015..746a7847c 100644
--- a/test/unit/builtin/filters/html.ts
+++ b/test/unit/builtin/filters/html.ts
@@ -1,4 +1,4 @@
-import { test, ctx, liquid } from 'test/stub/render'
+import { test } from 'test/stub/render'
 
 describe('filters/html', function () {
   describe('escape', function () {
diff --git a/test/unit/builtin/filters/math.ts b/test/unit/builtin/filters/math.ts
index 942302e67..61f977825 100644
--- a/test/unit/builtin/filters/math.ts
+++ b/test/unit/builtin/filters/math.ts
@@ -1,4 +1,4 @@
-import { test, ctx, liquid } from 'test/stub/render'
+import { test } from 'test/stub/render'
 
 describe('filters/math', function () {
   describe('abs', function () {
diff --git a/test/unit/builtin/filters/object.ts b/test/unit/builtin/filters/object.ts
index 671edf27f..122feb2a3 100644
--- a/test/unit/builtin/filters/object.ts
+++ b/test/unit/builtin/filters/object.ts
@@ -1,4 +1,4 @@
-import { test, ctx, liquid } from 'test/stub/render'
+import { test } from 'test/stub/render'
 
 describe('filters/object', function () {
   describe('default', function () {
diff --git a/test/unit/builtin/filters/string.ts b/test/unit/builtin/filters/string.ts
index c8baf3435..a424187f0 100644
--- a/test/unit/builtin/filters/string.ts
+++ b/test/unit/builtin/filters/string.ts
@@ -1,4 +1,4 @@
-import { test, ctx, liquid } from 'test/stub/render'
+import { test } from 'test/stub/render'
 
 describe('filters/string', function () {
   describe('append', function () {
diff --git a/test/unit/builtin/filters/url.ts b/test/unit/builtin/filters/url.ts
index 1c791c8db..02351197e 100644
--- a/test/unit/builtin/filters/url.ts
+++ b/test/unit/builtin/filters/url.ts
@@ -1,4 +1,4 @@
-import { test, ctx, liquid } from 'test/stub/render'
+import { test } from 'test/stub/render'
 
 describe('filters/url', function () {
   describe('url_decode', function () {