diff --git a/docs/guide/index.md b/docs/guide/index.md
index a793c90b2f79..0d95293de1ba 100644
--- a/docs/guide/index.md
+++ b/docs/guide/index.md
@@ -62,6 +62,10 @@ test('adds 1 + 2 to equal 3', () => {
 })
 ```
 
+::: tip
+By default, tests must contain ".test." or ".spec." in their file name.
+:::
+
 Next, in order to execute the test, add the following section to your `package.json`:
 
 ```json