Add primary route accessor method.

Author: Crell

src/Config.php

@@ -302,6 +302,26 @@ public function routes() : array
         return $this->routesDef;
     }
 
+    /**
+     * Returns the primary route.
+     *
+     * The primary route is the one marked primary in `routes.yaml`, or else
+     * the first non-redirect route in that file if none are marked.
+     *
+     * @return array
+     *   The route definition.  The generated URL of the route is added as a "url" key.
+     */
+    public function getPrimaryRoute() : array
+    {
+        foreach ($this->routes() as $url => $route) {
+            if ($route['primary'] == true) {
+                return $route;
+            }
+        }
+
+        throw new \InvalidArgumentException(sprintf('No primary route found. This isn\'t supposed to happen'));
+    }
+
     /**
      * Returns a single route definition.
      *

tests/ConfigTest.php

@@ -133,6 +133,17 @@ public function test_get_non_existent_route_throws_exception() : void
         $route = $config->getRoute('missing');
     }
 
+    public function test_primary_route_returns_correct_route() : void
+    {
+        $config = new Config($this->mockEnvironmentDeploy);
+
+        $route = $config->getPrimaryRoute();
+
+        $this->assertEquals('https://www.{default}/', $route['original_url']);
+        $this->assertEquals('main', $route['id']);
+        $this->assertTrue($route['primary']);
+    }
+
     public function test_onenterprise_returns_true_on_enterprise() : void
     {
         $env = $this->mockEnvironmentDeploy;