Add i18n-tasks with adapted config from CodeHarbor

spec/i18n_spec.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require 'i18n/tasks'
+
+RSpec.describe I18n do
+  let(:i18n) { I18n::Tasks::BaseTask.new }
+  let(:missing_keys) { i18n.missing_keys }
+  let(:unused_keys) { i18n.unused_keys }
+  let(:inconsistent_interpolations) { i18n.inconsistent_interpolations }
+
+  it 'does not have missing keys' do
+    expect(missing_keys).to be_empty,
+      "Missing #{missing_keys.leaves.count} I18n keys, " \
+      'run `i18n-tasks missing` to show them. ' \
+      'If this is a false positive, you can add exceptions for translation keys ' \
+      "in `config/i18n_tasks.yml` under 'ignore'. See https://github.com/glebm/i18n-tasks#configuration  " \
+      'for more details.'
+  end
+
+  it 'does not have unused keys' do
+    expect(unused_keys).to be_empty,
+      "#{unused_keys.leaves.count} unused I18n keys, run `i18n-tasks unused` to show them. " \
+      'If this is a false positive, you can add exceptions for translation keys ' \
+      "in `config/i18n_tasks.yml` under 'ignore_unused'. See https://github.com/glebm/i18n-tasks#configuration  " \
+      'for more details.'
+  end
+
+  it 'files are normalized' do
+    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 these.'
+    expect(non_normalized).to be_empty, error_message
+  end
+
+  it 'does not have inconsistent interpolations' do
+    error_message = "#{inconsistent_interpolations.leaves.count} i18n keys have inconsistent interpolations.\n" \
+                    'Run `i18n-tasks check-consistent-interpolations` to show them.'
+    expect(inconsistent_interpolations).to be_empty, error_message
+  end
+end