Articles about Ruby, Rails, testing, and developer tooling from the team behind RubyHash.https://rubyhash.dev/en-ushttps://rubyhash.dev/blog/timestamps-breaking-hash-equality/https://rubyhash.dev/blog/timestamps-breaking-hash-equality/Your test asserts two hashes are equal, the timestamps look identical, but it still fails. Here is why Ruby time values break hash equality and how to fix it.Fri, 10 Jul 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-symbol-vs-string-keys/https://rubyhash.dev/blog/ruby-symbol-vs-string-keys/In Ruby, :name and "name" are different hash keys, even though they look almost the same. That one distinction is behind a whole category of nil-returning, test-failing bugs.Sat, 27 Jun 2026 00:00:00 GMThttps://rubyhash.dev/blog/minitest-hash-diff-hard-to-read/https://rubyhash.dev/blog/minitest-hash-diff-hard-to-read/When a Minitest assertion fails on two hashes, the output is nearly unreadable. Here's why it happens and a faster way to find the one value that changed.Sat, 27 Jun 2026 00:00:00 GMThttps://rubyhash.dev/blog/compare-two-ruby-hashes/https://rubyhash.dev/blog/compare-two-ruby-hashes/Several ways to compare two Ruby hashes and find exactly what changed, from plain Ruby techniques to a visual side-by-side diff, with the tradeoffs of each.Sat, 27 Jun 2026 00:00:00 GMThttps://rubyhash.dev/blog/rails-test-hash-assertion-failing/https://rubyhash.dev/blog/rails-test-hash-assertion-failing/Your Rails test asserts two hashes are equal, they look identical, but the test still fails. Here's a checklist of the usual causes and how to find the real one.Sat, 27 Jun 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-equality-methods/https://rubyhash.dev/blog/ruby-equality-methods/Ruby has four different methods for asking whether two things are equal, and they don't mean the same thing. Knowing which is which explains case statements, hash keys, and a class of subtle bugs.Tue, 16 Jun 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-data-define/https://rubyhash.dev/blog/ruby-data-define/Ruby 3.2 added Data.define, a built-in way to create small immutable value objects. It's what Struct should have been, and it replaces a surprising amount of boilerplate.Mon, 01 Jun 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-reduce-vs-each-with-object/https://rubyhash.dev/blog/ruby-reduce-vs-each-with-object/Both reduce and each_with_object fold a collection into a single result, but they disagree about who owns the accumulator. Getting that wrong is the most common Enumerable bug there is.Fri, 29 May 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-memoization/https://rubyhash.dev/blog/ruby-memoization/The ||= memoization pattern is everywhere in Ruby code, and it quietly breaks on nil, false, and any method that takes arguments. Here is what actually happens and how to do it right.Tue, 19 May 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-hash-defaults/https://rubyhash.dev/blog/ruby-hash-defaults/Ruby hashes can carry their own default value or default block. Used well, they replace nil checks, initialization ceremony, and a surprising amount of glue code.Fri, 01 May 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-lazy-enumerators/https://rubyhash.dev/blog/ruby-lazy-enumerators/Ruby's lazy enumerators let you chain map, select, and reject on enormous datasets without loading everything into memory. Here's how they work and when to reach for them.Thu, 16 Apr 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-error-handling/https://rubyhash.dev/blog/ruby-error-handling/Most Ruby error handling is either too broad or too silent. Here's how to use rescue, retry, and custom exceptions to build code that fails clearly and recovers gracefully.Wed, 08 Apr 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-enumerable/https://rubyhash.dev/blog/ruby-enumerable/Ruby's Enumerable module gives you 50+ methods for free. Understanding it changes how you think about collections, pipelines, and data transformation.Tue, 31 Mar 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-hash-fetch/https://rubyhash.dev/blog/ruby-hash-fetch/Hash#[] silently returns nil for missing keys. Hash#fetch raises an error. That distinction prevents more bugs than you'd expect.Sun, 15 Mar 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-tap-then/https://rubyhash.dev/blog/ruby-tap-then/Ruby has three methods for building clean data pipelines: tap, then, and yield_self. Each does something slightly different, and knowing which to reach for makes your code more expressive.Wed, 25 Feb 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-duck-typing/https://rubyhash.dev/blog/ruby-duck-typing/Why Ruby's 'if it quacks like a duck' philosophy leads to more flexible, testable, and elegant code.Tue, 10 Feb 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-metaprogramming-line/https://rubyhash.dev/blog/ruby-metaprogramming-line/Ruby's metaprogramming is its most powerful and most dangerous feature. Here's how experienced teams decide when to use it and when to walk away.Sun, 18 Jan 2026 00:00:00 GMThttps://rubyhash.dev/blog/rails-concerns/https://rubyhash.dev/blog/rails-concerns/Concerns are controversial in the Rails world. They shouldn't be. The problem isn't the pattern, it's how people use it. Here's how to use concerns well.Mon, 05 Jan 2026 00:00:00 GMThttps://rubyhash.dev/blog/ruby-readability/https://rubyhash.dev/blog/ruby-readability/Ruby was designed to make programmers happy. That's not a slogan, it's a design philosophy that shaped how the language reads, and why that still matters.Thu, 11 Dec 2025 00:00:00 GMThttps://rubyhash.dev/blog/ruby-method-lookup/https://rubyhash.dev/blog/ruby-method-lookup/When you call a method in Ruby, there's a specific chain of places Ruby looks to find it. Understanding that chain is the key to debugging 'wrong method called' bugs.Fri, 03 Oct 2025 00:00:00 GMThttps://rubyhash.dev/blog/ruby-frozen-string-literal/https://rubyhash.dev/blog/ruby-frozen-string-literal/The frozen_string_literal pragma is one line of code that prevents mutation bugs, improves performance, and signals intent. Here's why you should be using it everywhere.Fri, 15 Aug 2025 00:00:00 GMThttps://rubyhash.dev/blog/ruby-testing-culture/https://rubyhash.dev/blog/ruby-testing-culture/Ruby didn't just popularize test-driven development, it made testing feel inevitable. Here's how a community obsession became an industry standard.Sun, 01 Jun 2025 00:00:00 GMThttps://rubyhash.dev/blog/custom-rake-tasks/https://rubyhash.dev/blog/custom-rake-tasks/Most Rake tasks are untested blobs of procedural code. Here's how to write ones that are namespaced, documented, testable, and actually maintainable.Tue, 22 Apr 2025 00:00:00 GMThttps://rubyhash.dev/blog/ruby-comparable/https://rubyhash.dev/blog/ruby-comparable/Include Comparable, define one method, and get six comparison operators plus sorting for free. It's one of Ruby's best-kept secrets for custom objects.Fri, 14 Feb 2025 00:00:00 GMThttps://rubyhash.dev/blog/debugging-activerecord/https://rubyhash.dev/blog/debugging-activerecord/N+1 queries, unnecessary column loading, and the count/size/length trap. These three patterns silently kill Rails performance, and they're easy to fix.Mon, 18 Nov 2024 00:00:00 GMThttps://rubyhash.dev/blog/ruby-pattern-matching/https://rubyhash.dev/blog/ruby-pattern-matching/Ruby 3's pattern matching with case/in isn't just syntax sugar. It's a fundamentally different way to destructure data, and it's been production-ready since 3.1.Thu, 05 Sep 2024 00:00:00 GMThttps://rubyhash.dev/blog/ruby-struct-vs-openstruct/https://rubyhash.dev/blog/ruby-struct-vs-openstruct/Ruby gives you two ways to create simple data objects. One is fast, explicit, and production-ready. The other is convenient, flexible, and almost always the wrong choice.Thu, 20 Jun 2024 00:00:00 GMThttps://rubyhash.dev/blog/welcome/https://rubyhash.dev/blog/welcome/Introducing RubyHash, a tool that turns unreadable Minitest hash diffs into clean, sorted, side-by-side comparisons so you can see exactly what changed.Mon, 15 Apr 2024 00:00:00 GMT