diff --git a/tests/src/Unit/OGImageManagerTest.php b/tests/src/Unit/OGImageManagerTest.php
new file mode 100644
index 000000000..68d70a466
--- /dev/null
+++ b/tests/src/Unit/OGImageManagerTest.php
@@ -0,0 +1,71 @@
+<?php
+
+namespace Drupal\Tests\helfi_platform_config\Unit;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\helfi_platform_config\Token\OGImageBuilderInterface;
+use Drupal\helfi_platform_config\Token\OGImageManager;
+use Drupal\Tests\token\Kernel\UnitTest;
+use Prophecy\Argument;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Prophecy\Prophecy\ObjectProphecy;
+
+/**
+ * Tests og image builder collector.
+ *
+ * @coversDefaultClass \Drupal\helfi_platform_config\Token\OGImageManager
+ * @group helfi_platform_config
+ */
+class OGImageManagerTest extends UnitTest {
+
+  use ProphecyTrait;
+
+  /**
+   * Tests builder.
+   *
+   * @covers ::buildUrl
+   * @covers ::add
+   * @covers ::getBuilders
+   */
+  public function testBuildUrl() : void {
+    $sut = new OGImageManager();
+    $entity = $this->prophesize(EntityInterface::class)->reveal();
+
+    // First builder does not apply.
+    $sut->add($this->createImageBuilder('1', FALSE)->reveal());
+    $this->assertEquals(NULL, $sut->buildUrl($entity));
+
+    // Second builder applies but returns NULL.
+    $sut->add($this->createImageBuilder(NULL)->reveal());
+    $this->assertEquals(NULL, $sut->buildUrl($entity));
+
+    // Third builder applies.
+    $sut->add($this->createImageBuilder('3')->reveal(), 100);
+    $this->assertEquals('3', $sut->buildUrl($entity));
+
+    // Builder with the highest priority gets overwritten by '3'.
+    $builder4 = $this->createImageBuilder('4');
+    $sut->add($builder4->reveal(), 200);
+    $this->assertEquals('3', $sut->buildUrl($entity));
+    $builder4->buildUrl(Argument::any())->shouldHaveBeenCalled();
+  }
+
+  /**
+   * Create image builder mock.
+   *
+   * @param string|null $url
+   *   Return value for buildUrl().
+   * @param bool $applies
+   *   Return value for applies().
+   *
+   * @return \Drupal\helfi_platform_config\Token\OGImageBuilderInterface|\Prophecy\Prophecy\ObjectProphecy
+   *   Builder mock.
+   */
+  private function createImageBuilder(?string $url, bool $applies = TRUE) : OGImageBuilderInterface|ObjectProphecy {
+    $builder = $this->prophesize(OGImageBuilderInterface::class);
+    $builder->applies(Argument::any())->willReturn($applies);
+    $builder->buildUrl(Argument::any())->willReturn($url);
+    return $builder;
+  }
+
+}