diff --git a/lib/rules/subsystem.js b/lib/rules/subsystem.js
index 92a7771..57f8a63 100644
--- a/lib/rules/subsystem.js
+++ b/lib/rules/subsystem.js
@@ -64,6 +64,7 @@ const validSubsystems = [
 , 'util'
 , 'v8'
 , 'vm'
+, 'worker'
 , 'zlib'
 ]
 
diff --git a/test/rules/subsystem.js b/test/rules/subsystem.js
new file mode 100644
index 0000000..a00c408
--- /dev/null
+++ b/test/rules/subsystem.js
@@ -0,0 +1,65 @@
+'use strict'
+
+const test = require('tap').test
+const Rule = require('../../lib/rules/subsystem')
+const Commit = require('gitlint-parser-node')
+const Validator = require('../../')
+
+test('rule: subsystem', (t) => {
+  t.test('invalid', (tt) => {
+    tt.plan(7)
+    const v = new Validator()
+    const context = new Commit({
+      sha: 'e7c077c610afa371430180fbd447bfef60ebc5ea'
+    , author: {
+        name: 'Evan Lucas'
+      , email: 'evanlucas@me.com'
+      , date: '2016-04-12T19:42:23Z'
+      }
+    , message: 'fhqwhgads: come on'
+    }, v)
+
+    context.report = (opts) => {
+      tt.pass('called report')
+      tt.equal(opts.id, 'subsystem', 'id')
+      tt.equal(opts.message, 'Invalid subsystem: "fhqwhgads"', 'message')
+      tt.equal(opts.string, 'fhqwhgads: come on', 'string')
+      tt.equal(opts.line, 0, 'line')
+      tt.equal(opts.column, 0, 'column')
+      tt.equal(opts.level, 'fail', 'level')
+      tt.end()
+    }
+
+    Rule.validate(context, {options: {subsystems: Rule.defaults.subsystems}})
+  })
+
+  t.test('valid', (tt) => {
+    tt.plan(2)
+
+    const v = new Validator()
+    const context = new Commit({
+      sha: 'e7c077c610afa371430180fbd447bfef60ebc5ea'
+    , author: {
+        name: 'Evan Lucas'
+      , email: 'evanlucas@me.com'
+      , date: '2016-04-12T19:42:23Z'
+      }
+    , message: 'worker: come on, fhqwhgads'
+    }, v)
+
+    context.report = (opts) => {
+      tt.pass('called report')
+      tt.strictSame(opts, {
+        id: 'subsystem'
+      , message: 'valid subsystems'
+      , string: 'worker'
+      , level: 'pass'
+      })
+      tt.end()
+    }
+
+    Rule.validate(context, {options: {subsystems: Rule.defaults.subsystems}})
+  })
+
+  t.end()
+})