diff --git a/tests/isObject.js b/tests/isObject.js
index 2c52d18..137e7d9 100644
--- a/tests/isObject.js
+++ b/tests/isObject.js
@@ -5,6 +5,7 @@ test('#isObject', () => {
 	ok(isObject({}));
 	ok(isObject([]));
 	ok(isObject(/anything else/));
+	ok(isObject(Object.create(null)));
 
 	ok(!isObject(undefined));
 	ok(!isObject(null));
diff --git a/tests/isPlainObject.js b/tests/isPlainObject.js
new file mode 100644
index 0000000..a1f815d
--- /dev/null
+++ b/tests/isPlainObject.js
@@ -0,0 +1,23 @@
+import {ok} from 'assert';
+import isPlainObject from '../isPlainObject';
+
+test('#isPlainObject', () => {
+	ok(isPlainObject({}));
+	ok(isPlainObject(Object.create(null)));
+
+	ok(!isPlainObject(undefined));
+	ok(!isPlainObject(null));
+	ok(!isPlainObject(false));
+	ok(!isPlainObject(true));
+	ok(!isPlainObject(''));
+	ok(!isPlainObject('1'));
+	ok(!isPlainObject(0));
+	ok(!isPlainObject(1));
+	ok(!isPlainObject(NaN));
+	ok(!isPlainObject(Infinity));
+	ok(!isPlainObject('non-empty string'));
+	ok(!isPlainObject([]));
+	ok(!isPlainObject(() => {}));
+	ok(!isPlainObject(function named() {}));
+	ok(!isPlainObject(/anything else/));
+});