Move PHPUnit tests into a tests/phpunit directory.

wp-tests-config.php can/should reside in the root of a develop checkout. `phpunit` should be run from the root.

see #25088.


git-svn-id: https://develop.svn.wordpress.org/trunk@25165 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/image/base.php

@@ -0,0 +1,50 @@
+<?php
+
+/**
+ * @group image
+ */
+abstract class WP_Image_UnitTestCase extends WP_UnitTestCase {
+
+	/**
+	 * Set the image editor engine according to the unit test's specification
+	 */
+	public function setUp() {
+		if ( ! call_user_func( array( $this->editor_engine, 'test' ) ) ) {
+			$this->markTestSkipped( sprintf('The image editor engine %s is not supported on this system', $this->editor_engine) );
+		}
+
+		add_filter( 'wp_image_editors', array( $this, 'setEngine' ), 10, 2 );
+	}
+
+	/**
+	 * Undo the image editor override
+	 */
+	public function tearDown() {
+		remove_filter( 'wp_image_editors', array( $this, 'setEngine' ), 10, 2 );
+	}
+
+	/**
+	 * Override the image editor engine
+	 * @return string
+	 */
+	public function setEngine( $editors ) {
+		return array( $this->editor_engine );
+	}
+
+	/**
+	 * Helper assertion for testing alpha on images
+	 * 
+	 * @param  string $image_path
+	 * @param  array $point      array(x,y)
+	 * @param  int $alpha
+	 */
+	protected function assertImageAlphaAtPoint( $image_path, $point, $alpha ) {
+
+		$im = imagecreatefrompng( $image_path );
+		$rgb = imagecolorat($im, $point[0], $point[1]);
+
+		$colors = imagecolorsforindex($im, $rgb);
+
+		$this->assertEquals( $alpha, $colors['alpha'] );
+	}
+}