From 2ff1827b6ea06968a189151092fa9df0435c4cfa Mon Sep 17 00:00:00 2001
From: Kunal Mehta <legoktm@member.fsf.org>
Date: Sat, 12 Jan 2019 11:35:02 -0800
Subject: [PATCH] registration: Allow overriding attributes in tests

ExtensionRegistry is a rather special singleton that can't use the normal
MediaWikiServices reset due to its early initialization, so introduce
a ->setAttributeForTest method to override attributes that are typically
loaded from extension.json.

Bug: T200013
Change-Id: I9e62a02ed2044c847e9ab2dcdfab094001f88986
---
 includes/registration/ExtensionRegistry.php   | 32 ++++++++++++++++++-
 .../registration/ExtensionRegistryTest.php    | 26 +++++++++++++++
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/includes/registration/ExtensionRegistry.php b/includes/registration/ExtensionRegistry.php
index e462a0bc85..e3bd54289c 100644
--- a/includes/registration/ExtensionRegistry.php
+++ b/includes/registration/ExtensionRegistry.php
@@ -1,6 +1,7 @@
 <?php
 
 use Composer\Semver\Semver;
+use Wikimedia\ScopedCallback;
 
 /**
  * ExtensionRegistry class
@@ -76,6 +77,13 @@ class ExtensionRegistry {
 	 */
 	protected $attributes = [];
 
+	/**
+	 * Attributes for testing
+	 *
+	 * @var array
+	 */
+	protected $testAttributes = [];
+
 	/**
 	 * @var ExtensionRegistry
 	 */
@@ -412,7 +420,29 @@ class ExtensionRegistry {
 	 * @return array
 	 */
 	public function getAttribute( $name ) {
-		return $this->attributes[$name] ?? [];
+		return $this->testAttributes[$name] ??
+			$this->attributes[$name] ?? [];
+	}
+
+	/**
+	 * Force override the value of an attribute during tests
+	 *
+	 * @param string $name Name of attribute to override
+	 * @param array $value Value to set
+	 * @return ScopedCallback to reset
+	 * @since 1.33
+	 */
+	public function setAttributeForTest( $name, array $value ) {
+		if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
+			throw new RuntimeException( __METHOD__ . ' can only be used in tests' );
+		}
+		if ( isset( $this->testAttributes[$name] ) ) {
+			throw new Exception( "The attribute '$name' has already been overridden" );
+		}
+		$this->testAttributes[$name] = $value;
+		return new ScopedCallback( function () use ( $name ) {
+			unset( $this->testAttributes[$name] );
+		} );
 	}
 
 	/**
diff --git a/tests/phpunit/includes/registration/ExtensionRegistryTest.php b/tests/phpunit/includes/registration/ExtensionRegistryTest.php
index 1baa79c160..5de1b0cb4b 100644
--- a/tests/phpunit/includes/registration/ExtensionRegistryTest.php
+++ b/tests/phpunit/includes/registration/ExtensionRegistryTest.php
@@ -1,5 +1,7 @@
 <?php
 
+use Wikimedia\ScopedCallback;
+
 /**
  * @covers ExtensionRegistry
  */
@@ -399,4 +401,28 @@ class ExtensionRegistryTest extends MediaWikiTestCase {
 			],
 		];
 	}
+
+	public function testSetAttributeForTest() {
+		$registry = new ExtensionRegistry();
+		$registry->queue( "{$this->dataDir}/good.json" );
+		$registry->loadFromQueue();
+		// Sanity check that it worked
+		$this->assertSame( [ 'test' ], $registry->getAttribute( 'FooBarAttr' ) );
+		$reset = $registry->setAttributeForTest( 'FooBarAttr', [ 'override' ] );
+		// overridden properly
+		$this->assertSame( [ 'override' ], $registry->getAttribute( 'FooBarAttr' ) );
+		ScopedCallback::consume( $reset );
+		// reset properly
+		$this->assertSame( [ 'test' ], $registry->getAttribute( 'FooBarAttr' ) );
+	}
+
+	/**
+	 * @expectedException Exception
+	 * @expectedExceptionMessage The attribute 'foo' has already been overridden
+	 */
+	public function testSetAttributeForTestDuplicate() {
+		$registry = new ExtensionRegistry();
+		$reset1 = $registry->setAttributeForTest( 'foo', [ 'val1' ] );
+		$reset2 = $registry->setAttributeForTest( 'foo', [ 'val2' ] );
+	}
 }
-- 
2.20.1