Adding some basic tests for prime number checker.

Author: blakeembrey

merge-sort/merge-sort.js

@@ -31,7 +31,7 @@ module.exports = function mergeSort (array, compare) {
       }
     }
     return result;
-  }
+  };
 
   return merge(mergeSort(left), mergeSort(right));
-}
+};

test/prime-number.js

@@ -0,0 +1,16 @@
+var primeNumber = require('../prime-number/prime-number'),
+    assert      = require('assert');
+
+describe('next highest number', function () {
+  it('should return true if the number is a prime number', function () {
+    assert.equal(primeNumber(859), true);
+    assert.equal(primeNumber(983), true);
+    assert.equal(primeNumber(283), true);
+  });
+
+  it('should return false if the number is not prime', function () {
+    assert.equal(primeNumber(324), false);
+    assert.equal(primeNumber(-124), false);
+    assert.equal(primeNumber(89325), false);
+  });
+});