--- /dev/null
+var test = require('tape')
+var isFunction = require('./index.js')
+
+test('isFunction', function (t) {
+ t.ok(!isFunction(), 'undefined is not a function')
+ t.ok(!isFunction(null), 'null is not a function')
+ t.ok(!isFunction(''), 'string is not a function')
+ t.ok(!isFunction(/a/), 'regex is not a function')
+ t.ok(!isFunction(true), 'true is not a function')
+ t.ok(!isFunction(false), 'false is not a function')
+ t.ok(!isFunction(NaN), 'NaN is not a function')
+ t.ok(!isFunction(42), '42 is not a function')
+ t.ok(isFunction(function () {}), 'function is a function')
+ t.ok(isFunction(setTimeout), 'setTimeout is a function')
+ t.end()
+})
+
+if (typeof window !== 'undefined') {
+ test('browser quirks', function (t) {
+ t.plan(2)
+
+ t.ok(isFunction(window.alert), 'alert is a function')
+
+ window.testRegExpFromIframe = function (regexp) {
+ t.ok(!isFunction(regexp))
+ }
+
+ var iframe = document.createElement('iframe')
+ document.body.appendChild(iframe)
+
+ iframe.contentWindow.document.write([
+ "<html><body><script type=\"text/javascript\">",
+ "parent.testRegExpFromIframe(/a/)",
+ "</script></body></html>"
+ ].join("\n"));
+ })
+}