MDL-49664 renderers: Verify expected render methods are called.

For various renderables (core, plugin, namespaced), all them
against the base and plugin renderers.

lib/tests/fixtures/namespaced_renderable.php

@@ -0,0 +1,25 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace something\largely\namespaced;
+
+defined('MOODLE_INTERNAL') || die;
+
+/**
+ * Simple namespaced renderable class to verify corresponding render methods are called correctly
+ */
+class renderable_test implements \renderable {
+}

lib/tests/outputcomponents_test.php

@@ -416,4 +416,45 @@ EOF;
         $this->assertEquals($expecteda, $pbara->pagelinks);
         $this->assertEquals($expectedb, $pbarb->pagelinks);
     }
+
+    public function test_renderer_method_names() {
+        global $CFG;
+        // Note, here we don't verify autoloading at all, but only that
+        // the renderers call to the correct methods no matter the renderable class
+        // is namespaced or no. Hence we are loading the needed fixtures manually.
+        require_once($CFG->dirroot . '/mod/assign/renderable.php');
+        require_once($CFG->libdir . '/tests/fixtures/namespaced_renderable.php');
+
+        // Array of renderable widgets to verify that renderers
+        // do call to the expected render method. Indexes are the expected
+        // method and values are the renderable instances.
+        $renderables = array(
+            'render_pix_icon' => new pix_icon('test', 'test'),                                     // A core one.
+            'render_assign_course_index_summary' => new assign_course_index_summary(true, 'test'), // A plugin one.
+            'render_renderable_test' => new \something\largely\namespaced\renderable_test(),       // A namespaced one.
+        );
+
+        // We are going to test all the renderables agains some different renderers.
+        $renderers = array(
+            'renderer_base',
+            'plugin_renderer_base'
+        );
+
+        // Run all combinations.
+        foreach ($renderables as $method => $renderable) {
+            foreach ($renderers as $renderer) {
+                // Create the double with the expected method mocked.
+                $stub = $this->getMockBuilder($renderer)
+                    ->disableOriginalConstructor()
+                    ->setMethods(array($method))
+                    ->getMock();
+                // Expect the method is called once and will return true.
+                $stub->expects($this->once())
+                    ->method($method)
+                    ->will($this->returnValue(true));
+                // Assert the return value and verify the expectation.
+                $this->assertTrue($stub->render($renderable));
+            }
+        }
+    }
 }