feat: Added the ability to create Instagram channel (#11182)

This PR is part of https://github.com/chatwoot/chatwoot/pull/11054 to
make the review cycle easier.

spec/helpers/instagram/integration_helper_spec.rb

@@ -0,0 +1,98 @@
+require 'rails_helper'
+
+RSpec.describe Instagram::IntegrationHelper do
+  include described_class
+
+  describe '#generate_instagram_token' do
+    let(:account_id) { 1 }
+    let(:client_secret) { 'test_secret' }
+    let(:current_time) { Time.current }
+
+    before do
+      allow(GlobalConfigService).to receive(:load).with('INSTAGRAM_APP_SECRET', nil).and_return(client_secret)
+      allow(Time).to receive(:current).and_return(current_time)
+    end
+
+    it 'generates a valid JWT token with correct payload' do
+      token = generate_instagram_token(account_id)
+      decoded_token = JWT.decode(token, client_secret, true, algorithm: 'HS256').first
+
+      expect(decoded_token['sub']).to eq(account_id)
+      expect(decoded_token['iat']).to eq(current_time.to_i)
+    end
+
+    context 'when client secret is not configured' do
+      let(:client_secret) { nil }
+
+      it 'returns nil' do
+        expect(generate_instagram_token(account_id)).to be_nil
+      end
+    end
+
+    context 'when an error occurs' do
+      before do
+        allow(JWT).to receive(:encode).and_raise(StandardError.new('Test error'))
+      end
+
+      it 'logs the error and returns nil' do
+        expect(Rails.logger).to receive(:error).with('Failed to generate Instagram token: Test error')
+        expect(generate_instagram_token(account_id)).to be_nil
+      end
+    end
+  end
+
+  describe '#token_payload' do
+    let(:account_id) { 1 }
+    let(:current_time) { Time.current }
+
+    before do
+      allow(Time).to receive(:current).and_return(current_time)
+    end
+
+    it 'returns a hash with the correct structure' do
+      payload = token_payload(account_id)
+
+      expect(payload).to be_a(Hash)
+      expect(payload[:sub]).to eq(account_id)
+      expect(payload[:iat]).to eq(current_time.to_i)
+    end
+  end
+
+  describe '#verify_instagram_token' do
+    let(:account_id) { 1 }
+    let(:client_secret) { 'test_secret' }
+    let(:valid_token) do
+      JWT.encode({ sub: account_id, iat: Time.current.to_i }, client_secret, 'HS256')
+    end
+
+    before do
+      allow(GlobalConfigService).to receive(:load).with('INSTAGRAM_APP_SECRET', nil).and_return(client_secret)
+    end
+
+    it 'successfully verifies and returns account_id from valid token' do
+      expect(verify_instagram_token(valid_token)).to eq(account_id)
+    end
+
+    context 'when token is blank' do
+      it 'returns nil' do
+        expect(verify_instagram_token('')).to be_nil
+        expect(verify_instagram_token(nil)).to be_nil
+      end
+    end
+
+    context 'when client secret is not configured' do
+      let(:client_secret) { nil }
+
+      it 'returns nil' do
+        expect(verify_instagram_token(valid_token)).to be_nil
+      end
+    end
+
+    context 'when token is invalid' do
+      it 'logs the error and returns nil' do
+        expect(Rails.logger).to receive(:error).with(/Unexpected error verifying Instagram token:/)
+        expect(verify_instagram_token('invalid_token')).to be_nil
+      end
+    end
+  end
+end