diff --git a/tests/SpyPostRequestSenderTest.php b/tests/SpyPostRequestSenderTest.php
index 1abec6c..9c1c89d 100644
--- a/tests/SpyPostRequestSenderTest.php
+++ b/tests/SpyPostRequestSenderTest.php
@@ -17,7 +17,7 @@
 class SpyPostRequestSenderTest extends TestCase {
 
 	public function testGetCalls(): void {
-		$spy = new SpyPostRequestSender( new StubPostRequestSender(  ) );
+		$spy = new SpyPostRequestSender( new StubPostRequestSender() );
 
 		$spy->post( 'http://first.url', [ 'foo' => 'bar' ] );
 		$spy->post( 'http://second.url', [ 'baz' => 'bah', 'pew' => 1337 ] );
diff --git a/tests/StubPostRequestSenderTest.php b/tests/StubPostRequestSenderTest.php
new file mode 100644
index 0000000..e257bc3
--- /dev/null
+++ b/tests/StubPostRequestSenderTest.php
@@ -0,0 +1,52 @@
+<?php
+
+declare( strict_types = 1 );
+
+namespace Jeroen\PostRequestSender\Tests;
+
+use Jeroen\PostRequestSender\StubPostRequestSender;
+use Jeroen\PostRequestSender\TestResponse;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \Jeroen\PostRequestSender\StubPostRequestSender
+ * @covers \Jeroen\PostRequestSender\PostRequest
+ * @covers \Jeroen\PostRequestSender\TestResponse
+ */
+class StubPostRequestSenderTest extends TestCase {
+
+	public function testDefaultResponse(): void {
+		$stubSender = new StubPostRequestSender();
+
+		$response = $stubSender->post( 'https://example.com', [ 'foo' => 'bar' ] );
+
+		$this->assertSame(
+			'',
+			$response->getBody()->getContents()
+		);
+
+		$this->assertSame(
+			200,
+			$response->getStatusCode()
+		);
+	}
+
+	public function testAlternativeResponse(): void {
+		$stubSender = new StubPostRequestSender(
+			new TestResponse( 'TestBody', 418 )
+		);
+
+		$response = $stubSender->post( 'https://example.com', [ 'foo' => 'bar' ] );
+
+		$this->assertSame(
+			'TestBody',
+			$response->getBody()->getContents()
+		);
+
+		$this->assertSame(
+			418,
+			$response->getStatusCode()
+		);
+	}
+
+}