diff --git a/src/BuildData.php b/src/BuildData.php
index dcb9416..996f5fe 100644
--- a/src/BuildData.php
+++ b/src/BuildData.php
@@ -44,7 +44,7 @@ class BuildData {
    */
   public function setModuleType($module_type) {
 
-    if ($module_type !== ModuleManager::TYPE_CORE || $module_type !== ModuleManager::TYPE_CONTRIB) {
+    if ($module_type !== ModuleManager::TYPE_CORE && $module_type !== ModuleManager::TYPE_CONTRIB) {
       throw new InvalidModuleTypeException();
     }
     else {
@@ -96,16 +96,18 @@ class BuildData {
 
   public function getBuildStatus() {
     $build_status = Generator::BUILD_BUILDING;
-
-
-    switch ($this->getBuildData()->state) {
-      case "failed":
-        $build_status = Generator::BUILD_FAILED;
-        break;
-
-      case "finished":
-        $build_status = Generator::BUILD_SUCCESSFUL;
-        break;
+    $build_data = $this->getBuildData();
+
+    if (is_object($build_data) && property_exists($build_data, 'state')) {
+      switch ($build_data->state) {
+        case "failed":
+          $build_status = Generator::BUILD_FAILED;
+          break;
+
+        case "finished":
+          $build_status = Generator::BUILD_SUCCESSFUL;
+          break;
+      }
     }
 
     return $build_status;
diff --git a/tests/src/Unit/BuildDataTest.php b/tests/src/Unit/BuildDataTest.php
new file mode 100644
index 0000000..d414766
--- /dev/null
+++ b/tests/src/Unit/BuildDataTest.php
@@ -0,0 +1,92 @@
+<?php
+
+namespace Drupal\Tests\drupal_coverage_core\Unit;
+
+use Drupal\drupal_coverage_core\BuildData;
+use Drupal\drupal_coverage_core\Exception\InvalidModuleTypeException;
+use Drupal\drupal_coverage_core\Generator;
+use Drupal\drupal_coverage_core\ModuleManager;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\drupal_coverage_core\BuildData
+ * @group drupal_coverage_core
+ */
+class BuildDataTest extends UnitTestCase  {
+
+  /**
+   * @var \Drupal\drupal_coverage_core\BuildData
+   */
+  protected $buildData;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+    $this->buildData = new BuildData();
+  }
+
+  /**
+   * Tests the setModuleType() method.
+   *
+   * @dataProvider moduleTypeProvider()
+   */
+  public function testSetModuleType($actual, $expected) {
+    if ($expected !== FALSE) {
+      $this->buildData->setModuleType($actual);
+      $this->assertEquals($expected, $this->buildData->getModuleType());
+    }
+    else {
+      $this->setExpectedException(InvalidModuleTypeException::class);
+      $this->buildData->setModuleType($actual);
+    }
+  }
+
+  /**
+   * Provides test data for testSetModuleType.
+   *
+   * @return array
+   *   The test data.
+   */
+  public function moduleTypeProvider() {
+    return [
+      // Provides a Contributed module type.
+      [ModuleManager::TYPE_CONTRIB, ModuleManager::TYPE_CONTRIB],
+      // Provides a Core module type.
+      [ModuleManager::TYPE_CORE, ModuleManager::TYPE_CORE],
+      // Provides a non-existing module type.
+      [$this->getRandomGenerator()->string(), FALSE]
+    ];
+  }
+
+  /**
+   * Tests the getBuildStatus() method.
+   *
+   * @dataProvider buildStatusProvider()
+   */
+  public function testGetBuildStatus($class, $expected) {
+    $this->buildData->setBuildData($class);
+    $this->assertEquals($expected, $this->buildData->getBuildStatus());
+  }
+
+  /**
+   * Provides test data for testGetBuildStatus.
+   *
+   * @return array
+   *   The test data.
+   */
+  public function buildStatusProvider() {
+    $build_data_1 = new \stdClass();
+    $build_data_2 = new \stdClass();
+    $build_data_1->state = "failed";
+    $build_data_2->state = "finished";
+
+    return [
+      "No build data" => [NULL, Generator::BUILD_BUILDING],
+      "Build data which has been failed" => [$build_data_1, Generator::BUILD_FAILED],
+      "Build data which has been finished" => [$build_data_2, Generator::BUILD_SUCCESSFUL],
+    ];
+  }
+
+}