diff --git a/test/union/union.test.js b/test/union/union.test.js
index 73427934a..fd6157918 100644
--- a/test/union/union.test.js
+++ b/test/union/union.test.js
@@ -5,10 +5,20 @@ test('Testing union', (t) => {
   //For more information on all the methods supported by tape
   //Please go to https://github.com/substack/tape
   t.true(typeof union === 'function', 'union is a Function');
-  t.deepEqual(union([1, 2, 3], [4, 3, 2]), [1, 2, 3, 4], "Returns every element that exists in any of the two arrays once");
-  //t.deepEqual(union(args..), 'Expected');
-  //t.equal(union(args..), 'Expected');
-  //t.false(union(args..), 'Expected');
-  //t.throws(union(args..), 'Expected');
+  t.deepEqual(union([1, 2, 3], [4, 3, 2]), [1, 2, 3, 4], "union([1, 2, 3], [4, 3, 2]) returns [1, 2, 3, 4]");
+  t.deepEqual(union('str', 'asd'), [ 's', 't', 'r', 'a', 'd' ], "union('str', 'asd') returns [ 's', 't', 'r', 'a', 'd' ]");
+  t.deepEqual(union([[], {}], [1, 2, 3]), [[], {}, 1, 2, 3], "union([[], {}], [1, 2, 3]) returns [[], {}, 1, 2, 3]");
+  t.deepEqual(union([], []), [], "union([], []) returns []");
+  t.throws(() => union(), 'union() throws an error');
+  t.throws(() => union(true, 'str'), 'union(true, str) throws an error');
+  t.throws(() => union('false', true), 'union(false, true) throws an error');
+  t.throws(() => union(123, {}), 'union(123, {}) throws an error');
+  t.throws(() => union([], {}), 'union([], {}) throws an error');
+  t.throws(() => union(undefined, null), 'union(undefined, null) throws an error');
+
+  let start = new Date().getTime();
+  union([1, 2, 3], [4, 3, 2]);
+  let end = new Date().getTime();
+  t.true((end - start) < 2000, 'union([1, 2, 3], [4, 3, 2]) takes less than 2s to run');
   t.end();
-});
\ No newline at end of file
+});