Module: Plushie::Test::Snapshot

Defined in:
lib/plushie/test/snapshot.rb

Overview

Snapshot and screenshot assertion helpers.

Tree hash snapshots compare a SHA-256 hash captured by the renderer against a golden file in test/snapshots/.sha256. Screenshot assertions do the same with pixel data hashes in test/screenshots/.sha256.

First run creates the golden file. Set PLUSHIE_UPDATE_SNAPSHOTS=1 or PLUSHIE_UPDATE_SCREENSHOTS=1 to update existing golden files.

Examples:

Assert a tree hash snapshot in a test

assert_tree_hash("counter_initial")

Assert a screenshot (skipped on mock backend)

assert_screenshot("counter_after_click")

Assert a full tree snapshot as JSON

assert_tree_snapshot(session.tree, "test/snapshots/counter.json")

Constant Summary collapse

SNAPSHOTS_DIR =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

Default directory for tree snapshot files.

"test/snapshots"
SCREENSHOTS_DIR =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

Default directory for screenshot files.

"test/screenshots"

Instance Method Summary collapse

Instance Method Details

#assert_screenshot(name, **opts) ⇒ Object

Compare a screenshot pixel hash against a stored golden value. No-op on mock backend (screenshots are meaningless without rendering).

Parameters:

  • name (String) —

    screenshot name (used as filename stem)



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# File 'lib/plushie/test/snapshot.rb', line 53

def assert_screenshot(name, **opts)
  return if Plushie::Test.backend == :mock

  response = session.screenshot(name, **opts)
  hash = response[:hash] || response["hash"]
  raise "screenshot returned no hash for #{name.inspect}" unless hash

  path = File.join(SCREENSHOTS_DIR, "#{name}.sha256")
  _assert_golden_hash(path, hash, update_env: "PLUSHIE_UPDATE_SCREENSHOTS")
end

#assert_tree_hash(name) ⇒ Object

Compare a tree hash from the renderer against a stored golden value. On first run, writes the golden file. Set PLUSHIE_UPDATE_SNAPSHOTS=1 to overwrite.

Parameters:

  • name (String) —

    snapshot name (used as filename stem)



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# File 'lib/plushie/test/snapshot.rb', line 40

def assert_tree_hash(name)
  response = session.tree_hash(name)
  hash = response[:hash] || response["hash"]
  raise "tree_hash returned no hash for #{name.inspect}" unless hash

  path = File.join(SNAPSHOTS_DIR, "#{name}.sha256")
  _assert_golden_hash(path, hash, update_env: "PLUSHIE_UPDATE_SNAPSHOTS")
end

#assert_tree_snapshot(tree, path) ⇒ Object

Compare a tree (as JSON) against a stored golden file. On first run, writes the golden file. Set PLUSHIE_UPDATE_SNAPSHOTS=1 to overwrite.

Parameters:

  • tree (Hash, Node) —

    the tree to snapshot

  • path (String) —

    path to the golden file (relative or absolute)



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# File 'lib/plushie/test/snapshot.rb', line 70

def assert_tree_snapshot(tree, path)
  tree = strip_meta(tree) unless tree.is_a?(String)
  json = tree.is_a?(String) ? tree : JSON.pretty_generate(tree)
  hash = Digest::SHA256.hexdigest(json)

  if !File.exist?(path) || ENV["PLUSHIE_UPDATE_SNAPSHOTS"]
    FileUtils.mkdir_p(File.dirname(path))
    File.write(path, json)
  else
    stored = File.read(path)
    stored_hash = Digest::SHA256.hexdigest(stored)
    assert_equal stored_hash, hash,
      "Tree snapshot mismatch for #{path}. Run with PLUSHIE_UPDATE_SNAPSHOTS=1 to update."
  end
end