diff --git a/build/acceptance/config/behat.yml b/build/acceptance/config/behat.yml
index 2ac1c077537..186a57c2023 100644
--- a/build/acceptance/config/behat.yml
+++ b/build/acceptance/config/behat.yml
@@ -6,6 +6,7 @@ default:
       paths:
         - %paths.base%/../features
       contexts:
+        - ActorContext
         - NextcloudTestServerContext
 
         - FeatureContext
diff --git a/build/acceptance/features/bootstrap/FeatureContext.php b/build/acceptance/features/bootstrap/FeatureContext.php
index b309a7e04b0..0598cbae959 100644
--- a/build/acceptance/features/bootstrap/FeatureContext.php
+++ b/build/acceptance/features/bootstrap/FeatureContext.php
@@ -23,6 +23,8 @@
 
 use Behat\Behat\Context\Context;
 
-class FeatureContext implements Context {
+class FeatureContext implements Context, ActorAwareInterface {
+
+	use ActorAware;
 
 }
diff --git a/build/acceptance/features/core/Actor.php b/build/acceptance/features/core/Actor.php
new file mode 100644
index 00000000000..0fea9be20c0
--- /dev/null
+++ b/build/acceptance/features/core/Actor.php
@@ -0,0 +1,92 @@
+<?php
+
+/**
+ *
+ * @copyright Copyright (c) 2017, Daniel Calviño Sánchez (danxuliu@gmail.com)
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/**
+ * An actor in a test scenario.
+ *
+ * Every Actor object is intended to be used only in a single test scenario.
+ * An Actor can control its web browser thanks to the Mink Session received when
+ * it was created, so in each scenario each Actor must have its own Mink
+ * Session; the same Mink Session can be used by different Actors in different
+ * scenarios, but never by different Actors in the same scenario.
+ *
+ * The test servers used in an scenario can change between different test runs,
+ * so an Actor stores the base URL for the current test server being used; in
+ * most cases the tests are specified using relative paths that can be converted
+ * to the appropriate absolute URL using locatePath() in the step
+ * implementation.
+ */
+class Actor {
+
+	/**
+	 * @var \Behat\Mink\Session
+	 */
+	private $session;
+
+	/**
+	 * @var string
+	 */
+	private $baseUrl;
+
+	/**
+	 * Creates a new Actor.
+	 *
+	 * @param \Behat\Mink\Session $session the Mink Session used to control its
+	 *        web browser.
+	 * @param string $baseUrl the base URL used when solving relative URLs.
+	 */
+	public function __construct(\Behat\Mink\Session $session, $baseUrl) {
+		$this->session = $session;
+		$this->baseUrl = $baseUrl;
+	}
+
+	/**
+	 * Sets the base URL.
+	 *
+	 * @param string $baseUrl the base URL used when solving relative URLs.
+	 */
+	public function setBaseUrl($baseUrl) {
+		$this->baseUrl = $baseUrl;
+	}
+
+	/**
+	 * Returns the Mink Session used to control its web browser.
+	 *
+	 * @return \Behat\Mink\Session the Mink Session used to control its web
+	 *         browser.
+	 */
+	public function getSession() {
+		return $this->session;
+	}
+
+	/**
+	 * Returns the full path for the given relative path based on the base URL.
+	 *
+	 * @param string relativePath the relative path.
+	 * @return string the full path.
+	 */
+	public function locatePath($relativePath) {
+		return $this->baseUrl . $relativePath;
+	}
+
+}
diff --git a/build/acceptance/features/core/ActorAware.php b/build/acceptance/features/core/ActorAware.php
new file mode 100644
index 00000000000..f1d355c1b0e
--- /dev/null
+++ b/build/acceptance/features/core/ActorAware.php
@@ -0,0 +1,38 @@
+<?php
+
+/**
+ *
+ * @copyright Copyright (c) 2017, Daniel Calviño Sánchez (danxuliu@gmail.com)
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+trait ActorAware {
+
+	/**
+	 * @var Actor
+	 */
+	private $actor;
+
+	/**
+	 * @param Actor $actor
+	 */
+	public function setCurrentActor(Actor $actor) {
+		$this->actor = $actor;
+	}
+
+}
diff --git a/build/acceptance/features/core/ActorAwareInterface.php b/build/acceptance/features/core/ActorAwareInterface.php
new file mode 100644
index 00000000000..9363bc3e607
--- /dev/null
+++ b/build/acceptance/features/core/ActorAwareInterface.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ *
+ * @copyright Copyright (c) 2017, Daniel Calviño Sánchez (danxuliu@gmail.com)
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+interface ActorAwareInterface {
+
+	/**
+	 * @param Actor $actor
+	 */
+	public function setCurrentActor(Actor $actor);
+
+}
diff --git a/build/acceptance/features/core/ActorContext.php b/build/acceptance/features/core/ActorContext.php
new file mode 100644
index 00000000000..e655911af67
--- /dev/null
+++ b/build/acceptance/features/core/ActorContext.php
@@ -0,0 +1,127 @@
+<?php
+
+/**
+ *
+ * @copyright Copyright (c) 2017, Daniel Calviño Sánchez (danxuliu@gmail.com)
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+use Behat\Behat\Hook\Scope\BeforeStepScope;
+use Behat\MinkExtension\Context\RawMinkContext;
+
+/**
+ * Behat context to set the actor used in sibling contexts.
+ *
+ * This helper context provides a step definition ("I act as XXX") to change the
+ * current actor of the scenario, which makes possible to use different browser
+ * sessions in the same scenario.
+ *
+ * Sibling contexts that want to have access to the current actor of the
+ * scenario must implement the ActorAwareInterface; this can be done just by
+ * using the ActorAware trait.
+ *
+ * Besides updating the current actor in sibling contexts the ActorContext also
+ * propagates its inherited "base_url" Mink parameter to the Actors as needed.
+ *
+ * Every actor used in the scenarios must have a corresponding Mink session
+ * declared in "behat.yml" with the same name as the actor. All used sessions
+ * are stopped after each scenario is run.
+ */
+class ActorContext extends RawMinkContext {
+
+	/**
+	 * @var array
+	 */
+	private $actors;
+
+	/**
+	 * @var Actor
+	 */
+	private $currentActor;
+
+	/**
+	 * Sets a Mink parameter.
+	 *
+	 * When the "base_url" parameter is set its value is propagated to all the
+	 * Actors.
+	 *
+	 * @param string $name the name of the parameter.
+	 * @param string $value the value of the parameter.
+	 */
+	public function setMinkParameter($name, $value) {
+		parent::setMinkParameter($name, $value);
+
+		if ($name === "base_url") {
+			foreach ($this->actors as $actor) {
+				$actor->setBaseUrl($value);
+			}
+		}
+	}
+
+	/**
+	 * @BeforeScenario
+	 *
+	 * Initializes the Actors for the new Scenario with the default Actor.
+	 *
+	 * Other Actors are added (and their Mink Sessions started) only when they
+	 * are used in an "I act as XXX" step.
+	 */
+	public function initializeActors() {
+		$this->actors = array();
+
+		$this->actors["default"] = new Actor($this->getSession(), $this->getMinkParameter("base_url"));
+
+		$this->currentActor = $this->actors["default"];
+	}
+
+	/**
+	 * @BeforeStep
+	 */
+	public function setCurrentActorInSiblingActorAwareContexts(BeforeStepScope $scope) {
+		$environment = $scope->getEnvironment();
+
+		foreach ($environment->getContexts() as $context) {
+			if ($context instanceof ActorAwareInterface) {
+				$context->setCurrentActor($this->currentActor);
+			}
+		}
+	}
+
+	/**
+	 * @Given I act as :actorName
+	 */
+	public function iActAs($actorName) {
+		if (!array_key_exists($actorName, $this->actors)) {
+			$this->actors[$actorName] = new Actor($this->getSession($actorName), $this->getMinkParameter("base_url"));
+		}
+
+		$this->currentActor = $this->actors[$actorName];
+	}
+
+	/**
+	 * @AfterScenario
+	 *
+	 * Stops all the Mink Sessions used in the last Scenario.
+	 */
+	public function cleanUpSessions() {
+		foreach ($this->actors as $actor) {
+			$actor->getSession()->stop();
+		}
+	}
+
+}