Add test coverage for identity token

tests/PHPUnit/Button/Endpoint/DataClientIdEndpointTest.php

@@ -0,0 +1,67 @@
+<?php
+declare(strict_types=1);
+
+namespace WooCommerce\PayPalCommerce\Button\Endpoint;
+
+use WooCommerce\PayPalCommerce\ApiClient\Endpoint\IdentityToken;
+use WooCommerce\PayPalCommerce\ApiClient\Entity\Token;
+use WooCommerce\PayPalCommerce\ApiClient\Exception\RuntimeException;
+use WooCommerce\PayPalCommerce\TestCase;
+use Mockery;
+use function Brain\Monkey\Functions\when;
+use function Brain\Monkey\Functions\expect;
+
+class DataClientIdEndpointTest extends TestCase
+{
+    private $requestData;
+    private $identityToken;
+    private $sut;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+        $this->requestData = Mockery::mock(RequestData::class);
+        $this->identityToken = Mockery::mock(IdentityToken::class);
+        $this->sut = new DataClientIdEndpoint($this->requestData, $this->identityToken);
+    }
+
+    public function testHandleRequestSuccess()
+    {
+        $userId = 1;
+        $token = Mockery::mock(Token::class);
+
+        $this->requestData->shouldReceive('read_request')
+            ->with($this->sut::nonce());
+        when('get_current_user_id')->justReturn($userId);
+        $this->identityToken->shouldReceive('generate_for_customer')
+            ->with($userId)
+            ->andReturn($token);
+
+        $token->shouldReceive('token')
+            ->andReturn('token');
+        $token->shouldReceive('expiration_timestamp')
+            ->andReturn(3600);
+        expect('wp_send_json')->with([
+            'token'      => $token->token(),
+            'expiration' => $token->expiration_timestamp(),
+            'user'       => $userId,
+        ]);
+
+        $result = $this->sut->handle_request();
+        $this->assertTrue($result);
+    }
+
+    public function testHandleRequestFails()
+    {
+        $userId = 1;
+        $this->requestData->shouldReceive('read_request')
+            ->with($this->sut::nonce());
+        when('get_current_user_id')->justReturn($userId);
+        $this->identityToken->shouldReceive('generate_for_customer')
+            ->andThrows(RuntimeException::class);
+        expect('wp_send_json_error');
+
+        $result = $this->sut->handle_request();
+        $this->assertFalse($result);
+    }
+}