Add Configure Tests To Run In Random Order as an RSpec TIL

rspec/configure-tests-to-run-in-random-order.md

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+# Configure Tests To Run In Random Order
+
+By default, an RSpec test suite is going to run in a predictable, sequential
+order, every time.
+
+When testing the parts of a complex Rails app that have all kinds of test data
+that needs to be set up, I prefer to have my tests always run in a random
+(repeatable with a seed) order. This way I'm more likely to catch sooner,
+rather than later, bugs that are hidden by passing tests due to test data setup
+that happens to work in a specific order.
+
+RSpec can be configured to run tests in a random, seedable order in the
+`spec_helper.rb` file.
+
+```ruby
+RSpec.configure do |config|
+  config.order = :random
+end
+```
+
+Whenever you run your test suite, the first thing you'll see is a message like
+this:
+
+```
+Randomized with seed 7011
+```
+
+That seed number can be used to re-run the suite in a repeatable order when you
+need to do so to track down an order-dependent failing test.
+
+```bash
+$ be rspec --seed 7011
+```