Most software companies struggle with releasing quality code that doesn't break critical user workflows.

Companies invest significant dollars in testing their product to counter this but often ship a P0 bug anyway.

Here are 5 root causes for software bugs.

#1 Inconsistent Testing Environments

A common mistake and often a harder one to fix during the nascent phases of software.

Naturally, if the pre-production environment never hits an edge case that can occur in production, it is impossible to validate enhancements accurately.

Thought: Deploy a snapshot of the production environment as a pre-release environment.

#2 Backwards Incompatibility

Engineering teams write code to work in the "present" and the "future", making version testing hard. Software should not be forward-facing.

Example: Release #1 deploys software with a v1 dependency, and release #2 now uses a v2 version of the dependency. This change is non-idempotent - we wipe out a variable value by storing only the latest state. 

What happens to the deployed state that works with a v1 dependency? Does it break or work with the new release?

Thought: Always support X states of existing data. Streamline rollbacks.

#3 Treating Infrastructure and Microservices Separately

As more folks campaign for infrastructure as code, we move towards automating infrastructure deployments.

But does a change in automation break existing infrastructure?

Thought: Can backward compatibility testing solve this problem?

#4 Ignoring the Network

Assuming the network behaves the same irrespective of time and region is a recipe for software failure.

Thought: Can Edge Testing gauge pre-release software inconsistencies?

#5 Testing Features in Silos

With the microservices architecture, a change in one service can cause a failure in unrelated user functionality. Testing a new release in a silo for a fixed subset of features doesn't help.

Thought: Replay tests for all critical user workflows for every release to generate an accurate failures heatmap.

Let me know if you've solved any of these mistakes and how.

Until later! :)