Add test to demonstrate the issue.

tests/phpunit/tests/admin/includes/wpGetPluginActionButton.php

@@ -0,0 +1,92 @@
+<?php
+
+/**
+ * Tests for wp_get_plugin_action_button().
+ *
+ * @group plugins
+ * @group admin
+ *
+ * @covers ::wp_get_plugin_action_button
+ */
+class Tests_Admin_Includes_WpGetPluginActionButton extends WP_UnitTestCase {
+
+	/**
+	 * Administrator user ID.
+	 *
+	 * @var int
+	 */
+	private static $admin_user_id;
+
+	/**
+	 * Test plugin data.
+	 *
+	 * @var stdClass
+	 */
+	private static $test_plugin;
+
+	/**
+	 * Sets up properties and adds a test plugin before any tests run.
+	 */
+	public static function set_up_before_class() {
+		parent::set_up_before_class();
+
+		require_once ABSPATH . 'wp-admin/includes/plugin-install.php';
+
+		self::$admin_user_id = self::factory()->user->create( array( 'role' => 'administrator' ) );
+		self::$test_plugin   = (object) array(
+			'name'    => 'My Plugin',
+			'slug'    => 'my-plugin',
+			'version' => '1.0.0',
+		);
+
+		mkdir( WP_PLUGIN_DIR . '/' . self::$test_plugin->slug );
+		file_put_contents(
+			WP_PLUGIN_DIR . '/' . self::$test_plugin->slug . '/my_plugin.php',
+			"<?php\n/**\n* Plugin Name: " . self::$test_plugin->name . "\n* Version: " . self::$test_plugin->version . "\n*/"
+		);
+	}
+
+	/**
+	 * Removes the test plugin and its directory after all tests run.
+	 */
+	public static function tear_down_after_class() {
+		parent::tear_down_after_class();
+
+		unlink( WP_PLUGIN_DIR . '/' . self::$test_plugin->slug . '/my_plugin.php' );
+		rmdir( WP_PLUGIN_DIR . '/' . self::$test_plugin->slug );
+	}
+
+	/**
+	 * Tests that an empty string is returned when the user does not have the
+	 * correct capabilities.
+	 *
+	 * @ticket
+	 */
+	public function test_should_return_empty_string_without_proper_capabilities() {
+		$actual = wp_get_plugin_action_button(
+			self::$test_plugin->name,
+			self::$test_plugin,
+			true,
+			true
+		);
+		$this->assertSame( '', $actual, 'No button markup should be returned.' );
+	}
+
+	/**
+	 * Tests that an empty string is not returned when the user has the
+	 * correct capabilities.
+	 *
+	 * @ticket
+	 */
+	public function test_should_not_return_empty_string_with_proper_capabilities() {
+		wp_set_current_user( self::$admin_user_id );
+
+		$actual = wp_get_plugin_action_button(
+			self::$test_plugin->name,
+			self::$test_plugin,
+			true,
+			true
+		);
+		$this->assertNotSame( '', $actual, 'Button markup should be returned.' );
+	}
+}