examples/edgeindex: move example from main to example_test (#706)

examples/edgeindex/README.md

@@ -8,3 +8,9 @@ street name to be unique under each city.
 ```console
 go generate ./...
 ```
+
+### Run Example
+
+```console
+go test
+```

examples/edgeindex/example_test.go

@@ -14,20 +14,21 @@ import (
 	_ "github.com/mattn/go-sqlite3"
 )
 
-func main() {
+func Example_EdgeIndex() {
 	client, err := ent.Open("sqlite3", "file:ent?mode=memory&cache=shared&_fk=1")
 	if err != nil {
 		log.Fatalf("failed opening connection to sqlite: %v", err)
 	}
 	defer client.Close()
 	ctx := context.Background()
-	// run the auto migration tool.
+	// Run the auto migration tool.
 	if err := client.Schema.Create(ctx); err != nil {
 		log.Fatalf("failed creating schema resources: %v", err)
 	}
 	if err := Do(ctx, client); err != nil {
 		log.Fatal(err)
 	}
+	// Output:
 }
 
 func Do(ctx context.Context, client *ent.Client) error {