diff --git a/test/types.js b/test/types.js
new file mode 100644
index 0000000..4b6c123
--- /dev/null
+++ b/test/types.js
@@ -0,0 +1,28 @@
+var assert = require('assert')
+var enforceType = require('../src/types')
+
+function CustomType() {}
+
+var types = ['Array', 'Boolean', 'Buffer', 'Number', 'String', CustomType]
+var values = [[], true, new Buffer(1), 1234, 'foobar', new CustomType()]
+
+describe('enforceType', function() {
+  types.forEach(function(type, i) {
+    describe(type, function() {
+      values.forEach(function(value, j) {
+        if (j === i) {
+          it('passes for ' + types[j], function() {
+            enforceType(type, value)
+          })
+
+        } else {
+          it('fails for ' + types[j], function() {
+            assert.throws(function() {
+              enforceType(type, value)
+            }, new RegExp('Expected ' + (type.name || type) + ', got '))
+          })
+        }
+      })
+    })
+  })
+})