A new mechanism is added, i18n-tasks, to check on translations

Gemfile

@@ -30,6 +30,7 @@ gem 'http_accept_language'
 gem 'rails-i18n'
 # Store some specific content, like application name and static pages contents
 gem 'i18n-active_record', require: 'i18n/active_record'
+gem 'i18n-tasks'
 # Remove leading and trailing white spaces
 gem 'strip_attributes'
 # Track changes to models' data

Gemfile.lock

@@ -181,6 +181,7 @@ GEM
       actionpack (>= 4.1)
       activesupport (>= 4.1)
     high_voltage (3.1.0)
+    highline (2.0.2)
     html2haml (2.2.0)
       erubis (~> 2.7.0)
       haml (>= 4.0, < 6)
@@ -203,6 +204,16 @@ GEM
     i18n-country-translations (1.3.1)
       i18n (>= 0.9.3, < 2)
       railties (>= 5.0, < 5.3)
+    i18n-tasks (0.9.29)
+      activesupport (>= 4.0.2)
+      ast (>= 2.1.0)
+      erubi
+      highline (>= 2.0.0)
+      i18n
+      parser (>= 2.2.3.0)
+      rails-i18n
+      rainbow (>= 2.2.2, < 4.0)
+      terminal-table (>= 1.5.1)
     icalendar (2.5.3)
       ice_cube (~> 0.16)
     inherited_resources (1.10.0)
@@ -396,13 +407,15 @@ GEM
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
-    sqlite3 (1.4.0)
+    sqlite3 (1.4.1)
     strip_attributes (1.9.0)
       activemodel (>= 3.0, < 7.0)
     sysexits (1.2.0)
     tagsinput-rails (1.3.5.1)
       railties (>= 3.1)
     temple (0.8.1)
+    terminal-table (1.8.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
     therubyracer (0.12.3)
       libv8 (~> 3.16.14.15)
       ref
@@ -476,6 +489,7 @@ DEPENDENCIES
   http_accept_language
   i18n-active_record
   i18n-country-translations
+  i18n-tasks
   icalendar
   ice_cube!
   jbuilder (~> 2.5)

config/i18n-tasks.yml

@@ -0,0 +1,134 @@
+# i18n-tasks finds and manages missing and unused translations: https://github.com/glebm/i18n-tasks
+
+# The "main" locale.
+base_locale: en
+## All available locales are inferred from the data by default. Alternatively, specify them explicitly:
+# locales: [es, fr]
+## Reporting locale, default: en. Available: en, ru.
+# internal_locale: en
+
+# Read and write translations.
+data:
+  ## Translations are read from the file system. Supported format: YAML, JSON.
+  ## Provide a custom adapter:
+  # adapter: I18n::Tasks::Data::FileSystem
+
+  # Locale files or `File.find` patterns where translations are read from:
+  read:
+    ## Default:
+    - config/locales/%{locale}.yml
+    ## More files:
+    - config/locales/*.%{locale}.yml
+    - config/locales/**/%{locale}.yml
+
+  # Locale files to write new keys to, based on a list of key pattern => file rules. Matched from top to bottom:
+  # `i18n-tasks normalize -p` will force move the keys according to these rules
+  write:
+    ## For example, write devise and simple form keys to their respective files:
+    - ['{devise, gflash, ice_cube, simple_form}.*', 'config/locales/\1.%{locale}.yml']
+    ## Catch-all default:
+    - config/locales/%{locale}.yml
+
+  # External locale data (e.g. gems).
+  # This data is not considered unused and is never written to.
+  external:
+    ## Example (replace %#= with %=):
+    # - "<%#= %x[bundle show vagrant].chomp %>/templates/locales/%{locale}.yml"
+
+  ## Specify the router (see Readme for details). Valid values: conservative_router, pattern_router, or a custom class.
+  # router: conservative_router
+
+  yaml:
+    write:
+      # do not wrap lines at 80 characters
+      line_width: -1
+
+  ## Pretty-print JSON:
+  # json:
+  #   write:
+  #     indent: '  '
+  #     space: ' '
+  #     object_nl: "\n"
+  #     array_nl: "\n"
+
+# Find translate calls
+search:
+  ## Paths or `File.find` patterns to search in:
+  # paths:
+  #  - app/
+
+  ## Root directories for relative keys resolution.
+  # relative_roots:
+  #   - app/controllers
+  #   - app/helpers
+  #   - app/mailers
+  #   - app/presenters
+  #   - app/views
+
+  ## Files or `File.fnmatch` patterns to exclude from search. Some files are always excluded regardless of this setting:
+  ##   %w(*.jpg *.png *.gif *.svg *.ico *.eot *.otf *.ttf *.woff *.woff2 *.pdf *.css *.sass *.scss *.less *.yml *.json)
+  exclude:
+    - app/assets/images
+    - app/assets/fonts
+    - app/assets/videos
+
+  ## Alternatively, the only files or `File.fnmatch patterns` to search in `paths`:
+  ## If specified, this settings takes priority over `exclude`, but `exclude` still applies.
+  # only: ["*.rb", "*.html.slim"]
+
+  ## If `strict` is `false`, guess usages such as t("categories.#{category}.title"). The default is `true`.
+  # strict: true
+
+  ## Multiple scanners can be used. Their results are merged.
+  ## The options specified above are passed down to each scanner. Per-scanner options can be specified as well.
+  ## See this example of a custom scanner: https://github.com/glebm/i18n-tasks/wiki/A-custom-scanner-example
+
+## Translation Services
+# translation:
+#   # Google Translate
+#   # Get an API key and set billing info at https://code.google.com/apis/console to use Google Translate
+#   google_translate_api_key: "AbC-dEf5"
+#   # DeepL Pro Translate
+#   # Get an API key and subscription at https://www.deepl.com/pro to use DeepL Pro
+#   deepl_api_key: "48E92789-57A3-466A-9959-1A1A1A1A1A1A"
+
+## Do not consider these keys missing:
+# ignore_missing:
+# - 'errors.messages.{accepted,blank,invalid,too_short,too_long}'
+# - '{devise,simple_form}.*'
+
+## Consider these keys used:
+ignore_unused:
+- 'activerecord.*'
+- '{devise,kaminari,gflash,ice_cube}.*'
+# - 'simple_form.{yes,no}'
+# - 'simple_form.{placeholders,hints,labels}.*'
+# - 'simple_form.{error_notification,required}.:'
+
+## Exclude these keys from the `i18n-tasks eq-base' report:
+# ignore_eq_base:
+#   all:
+#     - common.ok
+#   fr,es:
+#     - common.brand
+
+## Exclude these keys from the `i18n-tasks check-consistent-interpolations` report:
+# ignore_inconsistent_interpolations:
+# - 'activerecord.attributes.*'
+
+## Ignore these keys completely:
+ignore:
+- kaminari.*
+
+## Sometimes, it isn't possible for i18n-tasks to match the key correctly,
+## e.g. in case of a relative key defined in a helper method.
+## In these cases you can use the built-in PatternMapper to map patterns to keys, e.g.:
+#
+# <%# I18n::Tasks.add_scanner 'I18n::Tasks::Scanners::PatternMapper',
+#       only: %w(*.html.haml *.html.slim),
+#       patterns: [['= title\b', '.page_title']] %>
+#
+# The PatternMapper can also match key literals via a special %{key} interpolation, e.g.:
+#
+# <%# I18n::Tasks.add_scanner 'I18n::Tasks::Scanners::PatternMapper',
+#       patterns: [['\bSpree\.t[( ]\s*%{key}', 'spree.%{key}']] %>

test/i18n_test.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require 'i18n/tasks'
+
+class I18nTest < ActiveSupport::TestCase
+  def setup
+    @i18n = I18n::Tasks::BaseTask.new
+    @missing_keys = @i18n.missing_keys
+    @unused_keys = @i18n.unused_keys
+  end
+
+  def test_no_missing_keys
+    assert_empty @missing_keys,
+                 "Missing #{@missing_keys.leaves.count} i18n keys, run `i18n-tasks missing' to show them"
+  end
+
+  def test_no_unused_keys
+    assert_empty @unused_keys,
+                 "#{@unused_keys.leaves.count} unused i18n keys, run `i18n-tasks unused' to show them"
+  end
+
+  def test_files_are_normalized
+    non_normalized = @i18n.non_normalized_paths
+    error_message = "The following files need to be normalized:\n" \
+                    "#{non_normalized.map { |path| "  #{path}" }.join("\n")}\n" \
+                    "Please run `i18n-tasks normalize' to fix"
+    assert_empty non_normalized, error_message
+  end
+
+  def test_no_inconsistent_interpolations
+    inconsistent_interpolations = @i18n.inconsistent_interpolations
+    error_message = "#{inconsistent_interpolations.leaves.count} i18n keys have inconsistent interpolations.\n" \
+                    "Please run `i18n-tasks check-consistent-interpolations' to show them"
+    assert_empty inconsistent_interpolations, error_message
+  end
+end