Everyone Tests Now But Are We Testing the Right Things?

#ruby #rails #testing

Over the last 15 years, many companies phased out QA teams.

The idea: everyone is responsible for quality.

That pushed developers to write more tests, and tooling improved a lot.

But here’s the catch: high coverage doesn’t always mean high quality.

Coverage Isn’t Enough

Let’s take a simple example:

class User < ApplicationRecord
  def initials
    name.scan(/\b\w/).join
  end
end

With one test you can hit 100% coverage. Add a second for a negative case, and you’re done… right?

Not really.
If the name is José Ángel, this method only returns J.
If it’s 佐藤陽翔, it returns nothing.

Coverage reports look perfect. The user experience does not.

When QA teams disappeared, we lost something important: structured test design.

Most of us never formally learned it—we picked up “write some unit tests” or “learn a framework.”

But test design is about asking bigger questions:

Without that, testing becomes a numbers game: just write more tests.

Good testing isn’t about more tests. It’s about the right tests.
And that’s a skill every developer can (and should) learn.

👉 This is a shortened version of a longer article where I go deeper into: