The future of Walmart depends on walking into customers' houses when they aren't home and putting groceries in their fridge

Walmart's plan to take on Amazon involves entering customers' homes to restock groceries.

"In the future, we think we will be able to keep some customers' homes in stock, like we keep stores in stock today," Walmart CEO Doug McMillon said during the company's annual investor day on Tuesday.

In September, Walmart announced it is testing a service that delivers groceries straight to customers' fridges when they're not home.

"Think about that - someone else does the shopping for you AND puts it all away," Sloan Eddleston, Walmart's vice president of e-commerce strategy and business operations, wrote in a blog post.

In the test, which is a partnership with smart-lock startup August Home, a delivery person enters customers' homes to deliver orders and put groceries away in their refrigerators. The test is taking place in Silicon Valley with a small number of August Home users who have opted in to the service.

The Silicon Valley test is just one way that Walmart is trying to make itself an indispensable and convenient part of people's daily routine. The company has been making major investments in its e-commerce business as it faces off against an increasingly dominant Amazon.

On Tuesday, Walmart announced that it grew e-commerce sales in the US 12% in the first half of fiscal year 2017; the company estimates that sales will skyrocket 62% in the first half of 2018. Overall, in fiscal 2018, executives said the company expects to grow e-commerce sales by $11.8 billion.

"What might seem novel today could be the standard tomorrow," Eddleston said of the Silicon Valley test. "This may not be for everyone - and certainly not right away - but we want to offer customers the opportunity to participate in tests today and help us shape what commerce will look like in the future."