Add tests for Utilities::include_file(). (#227)

tests/phpunit/tests/Utilities/Utilities_IncludeFileTest.php

@@ -0,0 +1,37 @@
+<?php
+/**
+ * Class Utilities_IncludeFileTest
+ *
+ * @package AspireUpdate
+ */
+
+/**
+ * Tests for Utilities::include_file()
+ *
+ * @covers \AspireUpdate\Utilities::include_file
+ */
+class Utilities_IncludeFileTest extends WP_UnitTestCase {
+	/**
+	 * Test that a file is not included when an empty path has been provided.
+	 */
+	public function test_should_not_include_file_when_path_is_empty() {
+		$output = get_echo( [ 'AspireUpdate\Utilities', 'include_file' ], [ '' ] );
+		$this->assertEmpty( $output );
+	}
+
+	/**
+	 * Test that a file is not included when it does not exist.
+	 */
+	public function test_should_not_include_file_when_file_does_not_exist() {
+		$output = get_echo( [ 'AspireUpdate\Utilities', 'include_file' ], [ 'non-existent-file.php' ] );
+		$this->assertEmpty( $output );
+	}
+
+	/**
+	 * Test that a file is included.
+	 */
+	public function test_should_include_file() {
+		$output = get_echo( [ 'AspireUpdate\Utilities', 'include_file' ], [ 'page-admin-settings.php' ] );
+		$this->assertNotEmpty( $output );
+	}
+}