Add some types to test case

Author: Andy Wermke

test/sample.ts

@@ -1,5 +1,9 @@
 import test from 'ava'
 
-test('1 + 2 = 3', t => {
-  t.is(1 + 2, 3)
+function add (x: number, y: number): number {
+  return x + y
+}
+
+test('add(1, 2) = 3', t => {
+  t.is(add(1, 2), 3)
 })