What is inertia-rails-testing?

A testing guide for Ruby on Rails applications that use Inertia, a system for sending server-generated page data to a browser interface. It covers tests written with RSpec or Minitest.

It helps write controller, request, and integration tests for Inertia pages, including component checks, property matching, flash messages, deferred data, and partial page reloads.

It helps test what page a controller renders, which data and messages it sends, and whether private data is missing. It also avoids checking the wrong response when a request redirects before showing the page.

inertia-rails-testing — Skill by thecodingend/rails-starter

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add thecodingend/rails-starter --skill inertia-rails-testing

Clone the repo

git clone --depth 1 https://github.com/thecodingend/rails-starter

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/thecodingend/rails-starter/inertia-rails-testing/github.svg)](https://agentmods.dev/skills/thecodingend/rails-starter/inertia-rails-testing)

Your own site

<a href="https://agentmods.dev/skills/thecodingend/rails-starter/inertia-rails-testing"><img src="https://agentmods.dev/badge/skills/thecodingend/rails-starter/inertia-rails-testing/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/thecodingend/rails-starter/inertia-rails-testing"><img src="https://agentmods.dev/badge/skills/thecodingend/rails-starter/inertia-rails-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,551 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin 100% copy Near-identical to another mod in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00128	$0.01551
Opus 5.5	$0.00051	$0.00620
Sonnet 5.5	$0.00026	$0.00310
Haiku 4.5	$0.00013	$0.00155

Measured 2mo ago against content hash a527ef9463eb, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

inertia-rails-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to inertia-rails-testing — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/inertia-rails-testing/SKILL.md · 177 lines

How it starts

The opening of the file, as written. The whole thing — 177 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Inertia Rails Testing

Testing patterns for Inertia responses with RSpec and Minitest.

For each controller action, verify:

Correct component → render_component('users/index')
Expected props → have_props(users: satisfy { ... })
No leaked data → have_no_prop(:secret)
Flash messages → follow_redirect! then have_flash(notice: '...')
Deferred props → have_deferred_props(:analytics)

Common mistake: Forgetting follow_redirect! after PRG — without it, you're asserting against the 302 redirect response, not the Inertia page that follows.

Setup

# spec/rails_helper.rb
require 'inertia_rails/rspec'

RSpec Matchers

Matcher	Purpose
`be_inertia_response`	Verify response is Inertia format
`render_component('path')`	Check rendered component name
`have_props(key: value)`	Partial props match
`have_exact_props(key: value)`	Exact props match
`have_no_prop(:key)`	Assert prop absent
`have_flash(key: value)`	Partial flash match
`have_exact_flash(key: value)`	Exact flash match
`have_no_flash(:key)`	Assert flash absent
`have_deferred_props(:key)`	Check deferred props exist
`have_view_data(key: value)`	Partial view_data match

RSpec Examples

ALWAYS use matchers (render_component, have_props, have_flash) instead of direct property access (inertia.component, inertia.props[:key]):

# BAD — direct property access:
# expect(inertia.component).to eq('users/index')
# expect(inertia.props[:users].length).to eq(3)

# GOOD — use matchers:
expect(inertia).to render_component('users/index')
expect(inertia).to have_props(users: satisfy { |u| u.length == 3 })

# Key pattern: follow_redirect! after POST/PATCH/DELETE before asserting
it 'redirects with flash on success' do
  post users_path, params: { user: valid_params }

  expect(response).to redirect_to(users_path)
  follow_redirect!
  expect(inertia).to have_flash(notice: 'User created!')
end

it 'returns validation errors on failure' do
  post users_path, params: { user: { name: '' } }

  follow_redirect!
  expect(inertia).to have_props(errors: hash_including('name' => anything))
end

Read the full file on GitHub · 177 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

references/minitest.md 1.1 KB

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 177 lines · 128 tokens per session scan A a527ef9463eb

Subscribe to this mod's changes

inertia-rails-testing is a skill published in the GitHub repository thecodingend/rails-starter (5 stars, last pushed 2mo ago), licensed MIT. It adds 128 tokens to every session and 1,551 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to inertia-rails-testing, differing in 0 lines, and is treated as a copy.

Languages Ruby Testing Unit testing

inertia-rails-testing next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
inertia-rails-testingthecodingend/rails-starter	Skill	5	2mo ago	MIT	A	128	Claude Code, Codex
rspec-conventionsrootstrap/rails_api_base	Skill	634	2d ago	MIT	A	82	Claude Code
testunit-skillLambdaTest/agent-skills	Skill	390	yesterday	MIT	A	70	Claude Code, Codex
rubyMindrally/skills	Skill	297	29d ago	Apache-2.0	A	32	Claude Code
rspecMindrally/skills	Skill	297	29d ago	Apache-2.0	A	24	Claude Code
test-serviceigmarin/rails-agent-skills	Skill	29	1mo ago	MIT	A	36	Claude Code, Codex
write-testsigmarin/rails-agent-skills	Skill	29	1mo ago	MIT	A	37	Claude Code, Codex