diff --git a/.travis.yml b/.travis.yml
index 7e73268..5e262a1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,6 +7,7 @@ language: php
 php:
   - 7.1
   - 7.2
+  - 7.3
   - nightly
 
 matrix:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9ae1350..9c517b1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,14 @@
 Yii2 Workflow Change Log
 ==========================
 
+0.4.0 July 13, 2019
+
+- Brk: Methods now use the typecast supported in php 7.1
+
+0.3.2 December 18, 2018
+
+- fix version bump for yii2 roa tests
+
 0.3.1 December 17, 2018
 ------------------------
 
diff --git a/composer.json b/composer.json
index b77b38a..0f09c61 100644
--- a/composer.json
+++ b/composer.json
@@ -29,12 +29,10 @@
         }
     ],
     "require": {
-        "php": "^7.0",
-        "ext-curl": "*",
-        "tecnocen/yii2-roa": ">0.4.1",
+        "php": "^7.1",
+        "tecnocen/yii2-roa": "~0.5.0",
         "tecnocen/yii2-rmdb": "*",
-        "yii2tech/ar-softdelete": "*",
-        "yiisoft/yii2": "~2.0.10"
+        "yii2tech/ar-softdelete": "*"
     },
     "require-dev": {
         "codeception/base": "^2.2.11",
diff --git a/src/models/Assignment.php b/src/models/Assignment.php
index 67b2c89..aa6c636 100644
--- a/src/models/Assignment.php
+++ b/src/models/Assignment.php
@@ -4,6 +4,7 @@
 
 use tecnocen\rmdb\models\Pivot;
 use Yii;
+use yii\db\ActiveQuery;
 
 /**
  * @property int $process_id
@@ -16,7 +17,7 @@ abstract class Assignment extends Pivot
     /**
      * @return string class name for the process this worklog is attached to.
      */
-    protected abstract function processClass();
+    protected abstract function processClass(): string;
 
     /**
      * @inheritdoc
@@ -65,10 +66,11 @@ public function init()
         }
         parent::init();
     }
+
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getProcess()
+    public function getProcess(): ActiveQuery
     {
         return $this->hasOne($this->processClass(), ['id' => 'process_id']);
     }
diff --git a/src/models/Process.php b/src/models/Process.php
index 0046589..63f4b88 100644
--- a/src/models/Process.php
+++ b/src/models/Process.php
@@ -4,6 +4,7 @@
 
 use tecnocen\rmdb\models\Entity;
 use yii\base\InvalidConfigException;
+use yii\db\ActiveQuery;
 
 /**
  * Model class for process which change stages depending on a worklow
@@ -32,7 +33,7 @@ abstract class Process extends Entity
      * @return string full class name of the class to be used for the relation
      * `getWorkflow()`.
      */
-    public function workflowClass()
+    public function workflowClass(): string
     {
         return Workflow::class;
     }
@@ -41,18 +42,18 @@ public function workflowClass()
      * @return string full class name of the class to be used to store the
      * assignment records.
      */
-    protected abstract function assignmentClass();
+    protected abstract function assignmentClass(): string;
 
     /**
      * @return string full class name of the class to be used to store the
      * WorkLog records.
      */
-    protected abstract function WorkLogClass();
+    protected abstract function workLogClass(): string;
 
     /**
      * @return int the id of the workflow this process belongs to.
      */
-    public abstract function getWorkflowId();
+    public abstract function getWorkflowId(): int;
 
     /**
      * Determines if the current process record has the need of an initial
@@ -61,7 +62,7 @@ public abstract function getWorkflowId();
      *
      * @return bool whether the initial worklog was autogenerated.
      */
-    private function hasInitialWorkLog()
+    private function hasInitialWorkLog(): bool
     {
         if (!$this->autogenerateInitialWorklog || !$this->isNewRecord) {
             return false;
@@ -92,10 +93,10 @@ public function load($data, $formName = null)
     /**
      * Whether the user is asigned to the process.
      *
-     * @param int $userId [description]
-     * @return boolean
+     * @param ?int $userId
+     * @return bool
      */
-    public function userAssigned($userId)
+    public function userAssigned(?int $userId): bool
     {
         return !$this->getAssignments()->exists() || $this->getAssignments()
             ->andWhere(['user_id' => $userId]);
@@ -151,9 +152,9 @@ public function afterSave($insert, $changedAttributes)
      */
     public function init()
     {
-        if (!is_subclass_of($this->WorkLogClass(), WorkLog::class)) {
+        if (!is_subclass_of($this->workLogClass(), WorkLog::class)) {
             throw new InvalidConfigException(
-                static::class . '::WorkLogClass() must extend '
+                static::class . '::workLogClass() must extend '
                     . WorkLog::class
             );
         }
@@ -169,7 +170,7 @@ public function init()
     /**
      * @return Workflow
      */
-    public function getWorkflow()
+    public function getWorkflow(): Workflow
     {
         $workflowClass = $this->workflowClass();
 
@@ -177,9 +178,9 @@ public function getWorkflow()
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getAssignments()
+    public function getAssignments(): ActiveQuery
     {
         return $this->hasMany($this->assignmentClass(), [
             'process_id' => 'id',
@@ -187,27 +188,27 @@ public function getAssignments()
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getWorkLogs()
+    public function getWorkLogs(): ActiveQuery
     {
-        return $this->hasMany($this->WorkLogClass(), [
+        return $this->hasMany($this->workLogClass(), [
             'process_id' => 'id',
         ])->inverseOf('process');
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      * @see https://dev.mysql.com/doc/refman/5.7/en/example-maximum-column-group-row.html
      */
-    public function getActiveWorkLog()
+    public function getActiveWorkLog(): ActiveQuery
     {
         $query = $this->getWorkLogs()->alias('WorkLog');
         $query->multiple = false;
-        $WorkLogClass = $this->WorkLogClass();
+        $workLogClass = $this->workLogClass();
 
         return $query->andWhere([
-            'id' => $WorkLogClass::find()
+            'id' => $workLogClass::find()
                 ->select(['MAX(id)'])
                 ->alias('WorkLog_groupwise')
                 ->andWhere('WorkLog.process_id = WorkLog_groupwise.process_id')
@@ -222,29 +223,36 @@ public function getActiveWorkLog()
      * to create said WorkLog.
      * @param bool $runValidation
      */
-    public function flow(&$WorkLog, $runValidation = true)
+    public function flow(&$workLog, bool $runValidation = true)
     {
-        $WorkLog = $this->ensureWorkLog($WorkLog);
-        $WorkLog->scenario = WorkLog::SCENARIO_FLOW;
+        $workLog = $this->ensureWorkLog($workLog);
+        $workLog->scenario = WorkLog::SCENARIO_FLOW;
 
-        return $WorkLog->save($runValidation);
+        return $workLog->save($runValidation);
     }
 
-    private function ensureWorkLog($WorkLog)
+    /**
+     * Ensures that the provided parameter is either an array to create a valid
+     * instance of the `workLogClass()` class.
+     *
+     * @param array|WorkLog $workLog
+     * @return WorkLog extending the class defined in `workLogClass()`
+     */
+    private function ensureWorkLog($workLog): WorkLog
     {
-        $WorkLogClass = $this->WorkLogClass();
-        if (is_array($WorkLog)) {
-            $WorkLog = new $WorkLogClass($WorkLog);
-        } elseif (!$WorkLog instanceof $WorkLogClass) {
+        $workLogClass = $this->workLogClass();
+        if (is_array($workLog)) {
+            $workLog = new $workLogClass($workLog);
+        } elseif (!$workLog instanceof $workLogClass) {
             throw new InvalidParamException(
-                "Parameter must be an instance of {$WorkLogClass} or an "
+                "Parameter must be an instance of {$workLogClass} or an "
                     . 'array to configure an instance'
             );
         }
 
-        $WorkLog->process_id = $this->id;
-        $WorkLog->populateRelation('process', $this);
+        $workLog->process_id = $this->id;
+        $workLog->populateRelation('process', $this);
 
-        return $WorkLog;
+        return $workLog;
     }
 }
diff --git a/src/models/Stage.php b/src/models/Stage.php
index 692fbe3..0a57fa8 100644
--- a/src/models/Stage.php
+++ b/src/models/Stage.php
@@ -1,6 +1,9 @@
 <?php
 
 namespace tecnocen\workflow\models;
+
+use yii\db\ActiveQuery;
+
 /**
  * Model class for table `{{%workflow_stage}}`
  *
@@ -89,9 +92,9 @@ public function attributeLabels()
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getWorkflow()
+    public function getWorkflow(): ActiveQuery
     {
         return $this->hasOne(
             $this->workflowClass,
@@ -100,9 +103,9 @@ public function getWorkflow()
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getTransitions()
+    public function getTransitions(): ActiveQuery
     {
         return $this->hasMany(
             $this->transitionClass,
@@ -111,9 +114,9 @@ public function getTransitions()
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getDetailTransitions()
+    public function getDetailTransitions(): ActiveQuery
     {
         $query = $this->getTransitions();
         $query->multiple = false;
@@ -129,15 +132,15 @@ public function getDetailTransitions()
     /**
      * @return int
      */
-    public function getTotalTransitions()
+    public function getTotalTransitions(): int
     {
         return (int)$this->detailTransitions['totalTransitions'];
     }
 
     /**
-     * @return \yii\db\ActiveQuery sibling stages for the same workflow
+     * @return ActiveQuery sibling stages for the same workflow
      */
-    public function getSiblings()
+    public function getSiblings(): ActiveQuery
     {
         return $this->hasMany(static::class, ['workflow_id' => 'workflow_id'])
             ->alias('siblings');
diff --git a/src/models/Transition.php b/src/models/Transition.php
index 4b03229..2275339 100644
--- a/src/models/Transition.php
+++ b/src/models/Transition.php
@@ -3,6 +3,7 @@
 namespace tecnocen\workflow\models;
 
 use Yii;
+use yii\db\ActiveQuery;
 
 /**
  * Model class for table `{{%workflow_transition}}`
@@ -126,13 +127,14 @@ public function rules()
      *
      * @param int $userId
      * @param Process $process
-     * @return boolean
+     * @return bool
      */
-    public function userCan($userId, Process  $process)
+    public function userCan(?int $userId, Process  $process): bool
     {
         if (!$this->getPermissions()->exists()) {
             return true;
         }
+
         $authManager = Yii::$app->authManager;
 
         foreach ($this->permissions as $permission) {
@@ -160,25 +162,25 @@ public function attributeLabels()
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getSourceStage()
+    public function getSourceStage(): ActiveQuery
     {
         return $this->hasOne($this->stageClass, ['id' => 'source_stage_id']);
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getTargetStage()
+    public function getTargetStage(): ActiveQuery
     {
         return $this->hasOne($this->stageClass, ['id' => 'target_stage_id']);
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getPermissions()
+    public function getPermissions(): ActiveQuery
     {
         return $this->hasMany(
             $this->permissionClass,
diff --git a/src/models/TransitionPermission.php b/src/models/TransitionPermission.php
index 12a9351..1deb3b6 100644
--- a/src/models/TransitionPermission.php
+++ b/src/models/TransitionPermission.php
@@ -2,6 +2,8 @@
 
 namespace tecnocen\workflow\models;
 
+use yii\db\ActiveQuery;
+
 /**
  * Model class for table `{{%workflow_transition}}`
  *
@@ -116,25 +118,25 @@ public function attributeLabels()
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getSourceStage()
+    public function getSourceStage(): ActiveQuery
     {
         return $this->hasOne($this->stageClass, ['id' => 'source_stage_id']);
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getTargetStage()
+    public function getTargetStage(): ActiveQuery
     {
         return $this->hasOne($this->stageClass, ['id' => 'target_stage_id']);
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getTransition()
+    public function getTransition(): ActiveQuery
     {
         return $this->hasOne(
             $this->transitionClass,
diff --git a/src/models/WorkLog.php b/src/models/WorkLog.php
index d01ffc6..a25f4d4 100644
--- a/src/models/WorkLog.php
+++ b/src/models/WorkLog.php
@@ -4,6 +4,7 @@
 
 use tecnocen\rmdb\models\Pivot;
 use Yii;
+use yii\db\ActiveQuery;
 use yii\web\ForbiddenHttpException;
 use yii\web\BadRequestHttpException;
 
@@ -22,7 +23,7 @@ abstract class WorkLog extends Pivot
     /**
      * @return string class name for the process this worklog is attached to.
      */
-    protected abstract function processClass();
+    protected abstract function processClass(): string;
 
     /**
      * @inheritdoc
@@ -138,9 +139,9 @@ public function init()
         parent::init();
     }
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getProcess()
+    public function getProcess(): ActiveQuery
     {
         return $this->hasOne($this->processClass(), ['id' => 'process_id']);
     }
diff --git a/src/models/Workflow.php b/src/models/Workflow.php
index 176dc88..e9b53f8 100644
--- a/src/models/Workflow.php
+++ b/src/models/Workflow.php
@@ -2,6 +2,8 @@
 
 namespace tecnocen\workflow\models;
 
+use yii\db\ActiveQuery;
+
 /**
  * Model class for table `{{%workflow}}`
  *
@@ -58,18 +60,18 @@ public function attributeLabels()
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getStages()
+    public function getStages(): ActiveQuery
     {
         return $this->hasMany($this->stageClass, ['workflow_id' => 'id'])
             ->inverseOf('workflow');
     }
 
     /**
-     * @return \yii\db\ActiveQuery
+     * @return ActiveQuery
      */
-    public function getDetailStages()
+    public function getDetailStages(): ActiveQuery
     {
         $query = $this->getStages();
         $query->multiple = false;
@@ -85,7 +87,7 @@ public function getDetailStages()
     /**
      * @return int
      */
-    public function getTotalStages()
+    public function getTotalStages(): int
     {
         return (int)$this->detailStages['totalStages'];
     }
diff --git a/src/roa/models/Stage.php b/src/roa/models/Stage.php
index a266a1c..d863247 100644
--- a/src/roa/models/Stage.php
+++ b/src/roa/models/Stage.php
@@ -8,9 +8,6 @@
 
 /**
  * ROA contract to handle workflow stage records.
- *
- * @method string[] getSlugLinks()
- * @method string getSelfLink()
  */
 class Stage extends base\Stage implements Contract
 {
@@ -18,14 +15,6 @@ class Stage extends base\Stage implements Contract
         getLinks as getContractLinks;
     }
 
-    /**
-     * @inheritdoc
-     */
-    public function fields()
-    {
-        return array_merge($this->attributes(), ['totalTransitions']);
-    }
-
     /**
      * @inheritdoc
      */
@@ -39,7 +28,7 @@ public function fields()
     /**
      * @inheritdoc
      */
-    public function slugBehaviorConfig()
+    protected function slugBehaviorConfig(): array
     {
         return [
             'resourceName' => 'stage',
diff --git a/src/roa/models/StageSearch.php b/src/roa/models/StageSearch.php
index 42c04cd..df642f0 100644
--- a/src/roa/models/StageSearch.php
+++ b/src/roa/models/StageSearch.php
@@ -2,6 +2,7 @@
 
 namespace tecnocen\workflow\roa\models;
 
+use tecnocen\roa\ResourceSearch;
 use yii\data\ActiveDataProvider;
 use yii\web\NotFoundHttpException;
 
@@ -12,7 +13,6 @@
  */
 class StageSearch extends Stage implements \tecnocen\roa\ResourceSearch
 {
-
     /**
      * @inhertidoc
      */
@@ -27,15 +27,19 @@ public function rules()
     /**
      * @inhertidoc
      */
-    public function search(array $params, $formName = '')
-    {
+    public function search(
+        array $params,
+        ?string $formName = ''
+    ): ?ActiveDataProvider {
         $this->load($params, $formName);
         if (!$this->validate()) {
             return null;
         }
+
         if (null === $this->workflow) {
             throw new NotFoundHttpException('Unexistant workflow path.');
         }
+
         $class = get_parent_class();
         return new ActiveDataProvider([
             'query' => $class::find()->andFilterWhere([
diff --git a/src/roa/models/Transition.php b/src/roa/models/Transition.php
index 82ea1a1..c630bee 100644
--- a/src/roa/models/Transition.php
+++ b/src/roa/models/Transition.php
@@ -8,9 +8,6 @@
 
 /**
  * ROA contract to handle workflow transitions records.
- *
- * @method string[] getSlugLinks()
- * @method string getSelfLink()
  */
 class Transition extends base\Transition implements Contract
 {
@@ -31,7 +28,7 @@ class Transition extends base\Transition implements Contract
     /**
      * @inheritdoc
      */
-    protected function slugBehaviorConfig()
+    protected function slugBehaviorConfig(): array
     {
         return [
             'resourceName' => 'transition',
diff --git a/src/roa/models/TransitionPermission.php b/src/roa/models/TransitionPermission.php
index 073cdf2..0ba790f 100644
--- a/src/roa/models/TransitionPermission.php
+++ b/src/roa/models/TransitionPermission.php
@@ -8,15 +8,10 @@
 
 /**
  * ROA contract to handle workflow transition permissions records.
- *
- * @method string[] getSlugLinks()
- * @method string getSelfLink()
  */
 class TransitionPermission extends base\TransitionPermission implements Contract
 {
-    use ContractTrait {
-        getLinks as getContractLinks;
-    }
+    use ContractTrait;
 
     /**
      * @inheritdoc
@@ -31,7 +26,7 @@ class TransitionPermission extends base\TransitionPermission implements Contract
     /**
      * @inheritdoc
      */
-    public function slugBehaviorConfig()
+    protected function slugBehaviorConfig(): array
     {
         return [
             'idAttribute' => 'permission',
@@ -40,14 +35,6 @@ public function slugBehaviorConfig()
         ];
     }
 
-    /**
-     * @inheritdoc
-     */
-    public function getLinks()
-    {
-        return array_merge($this->getContractLinks());
-    }
-
     /**
      * @inheritdoc
      */
diff --git a/src/roa/models/TransitionPermissionSearch.php b/src/roa/models/TransitionPermissionSearch.php
index fc36d84..53aeb1a 100644
--- a/src/roa/models/TransitionPermissionSearch.php
+++ b/src/roa/models/TransitionPermissionSearch.php
@@ -2,6 +2,7 @@
 
 namespace tecnocen\workflow\roa\models;
 
+use tecnocen\roa\ResourceSearch;
 use yii\data\ActiveDataProvider;
 use yii\web\NotFoundHttpException;
 
@@ -10,10 +11,9 @@
  *
  * @author Angel (Faryshta) Guevara <aguevara@alquimiadigital.mx>
  */
-class TransitionPermissionSearch extends TransitionPermission
-    implements \tecnocen\roa\ResourceSearch
+class TransitionPermissionSearch extends TransitionPermission implements
+    ResourceSearch
 {
-
     /**
      * @inhertidoc
      */
@@ -28,8 +28,10 @@ public function rules()
     /**
      * @inhertidoc
      */
-    public function search(array $params, $formName = '')
-    {
+    public function search(
+        array $params,
+        ?string $formName = ''
+    ): ?ActiveDataProvider {
         $this->load($params, $formName);
         if (!$this->validate()) {
             return null;
diff --git a/src/roa/models/TransitionSearch.php b/src/roa/models/TransitionSearch.php
index f52d954..a29899d 100644
--- a/src/roa/models/TransitionSearch.php
+++ b/src/roa/models/TransitionSearch.php
@@ -28,8 +28,10 @@ public function rules()
     /**
      * @inhertidoc
      */
-    public function search(array $params, $formName = '')
-    {
+    public function search(
+        array $params,
+        ?string $formName = ''
+    ): ?ActiveDataProvider {
         $this->load($params, $formName);
         if (!$this->validate()) {
             return null;
diff --git a/src/roa/models/Workflow.php b/src/roa/models/Workflow.php
index c410fb5..7d13385 100644
--- a/src/roa/models/Workflow.php
+++ b/src/roa/models/Workflow.php
@@ -9,9 +9,6 @@
 
 /**
  * ROA contract to handle workflow records.
- *
- * @method string[] getSlugLinks()
- * @method string getSelfLink()
  */
 class Workflow extends base\Workflow implements Contract
 {
@@ -19,14 +16,6 @@ class Workflow extends base\Workflow implements Contract
         getLinks as getContractLinks;
     }
 
-    /**
-     * @inheritdoc
-     */
-    public function fields()
-    {
-        return array_merge($this->attributes(), ['totalStages']);
-    }
-
     /**
      * @inheritdoc
      */
@@ -35,7 +24,7 @@ public function fields()
     /**
      * @inheritdoc
      */
-    public function slugBehaviorConfig()
+    protected function slugBehaviorConfig(): array
     {
         return [
             'resourceName' => 'workflow',
@@ -44,10 +33,10 @@ public function slugBehaviorConfig()
                     && $this->id != $params['workflow_id']
                 ) {
                     throw new NotFoundHttpException(
-                       'Workflow not associated to element.'
+                        'Workflow not associated to element.'
                     );
                 }
-            }
+            },
         ];
     }
 
diff --git a/src/roa/models/WorkflowSearch.php b/src/roa/models/WorkflowSearch.php
index 62ee7c1..a49e969 100644
--- a/src/roa/models/WorkflowSearch.php
+++ b/src/roa/models/WorkflowSearch.php
@@ -2,6 +2,7 @@
 
 namespace tecnocen\workflow\roa\models;
 
+use tecnocen\roa\ResourceSearch;
 use yii\data\ActiveDataProvider;
 
 /**
@@ -9,9 +10,8 @@
  *
  * @author Angel (Faryshta) Guevara <aguevara@alquimiadigital.mx>
  */
-class WorkflowSearch extends Workflow implements \tecnocen\roa\ResourceSearch
+class WorkflowSearch extends Workflow implements ResourceSearch
 {
-
     /**
      * @inhertidoc
      */
@@ -26,12 +26,15 @@ public function rules()
     /**
      * @inhertidoc
      */
-    public function search(array $params, $formName = '')
-    {
+    public function search(
+        array $params,
+        ?string $formName = ''
+    ): ?ActiveDataProvider {
         $this->load($params, $formName);
         if (!$this->validate()) {
             return null;
         }
+
         $class = get_parent_class();
         return new ActiveDataProvider([
             'query' => $class::find()->andFilterWhere([
diff --git a/src/roa/modules/Version.php b/src/roa/modules/Version.php
index 862238f..7f9c370 100644
--- a/src/roa/modules/Version.php
+++ b/src/roa/modules/Version.php
@@ -2,10 +2,12 @@
 
 namespace tecnocen\workflow\roa\modules;
 
-use tecnocen\workflow\roa\resources\PermissionResource;
-use tecnocen\workflow\roa\resources\StageResource;
-use tecnocen\workflow\roa\resources\TransitionResource;
-use tecnocen\workflow\roa\resources\WorkflowResource;
+use tecnocen\workflow\roa\resources\{
+    PermissionResource,
+    StageResource,
+    TransitionResource,
+    WorkflowResource
+};
 
 class Version extends \tecnocen\roa\modules\ApiVersion
 {
diff --git a/src/roa/resources/PermissionResource.php b/src/roa/resources/PermissionResource.php
index 0a28f47..7b312d5 100644
--- a/src/roa/resources/PermissionResource.php
+++ b/src/roa/resources/PermissionResource.php
@@ -2,16 +2,16 @@
 
 namespace tecnocen\workflow\roa\resources;
 
-use Yii;
 use tecnocen\workflow\roa\models\TransitionPermission;
 use tecnocen\workflow\roa\models\TransitionPermissionSearch;
+use tecnocen\roa\controllers\Resource;
 
 /**
  * Resource to assign permissions to a transition.
  *
  * @author Angel (Faryshta) Guevara <aguevara@alquimiadigital.mx>
  */
-class PermissionResource extends \tecnocen\roa\controllers\Resource
+class PermissionResource extends Resource
 {
     /**
      * @inheritdoc
diff --git a/src/roa/resources/StageResource.php b/src/roa/resources/StageResource.php
index cebebf8..1aa0850 100644
--- a/src/roa/resources/StageResource.php
+++ b/src/roa/resources/StageResource.php
@@ -2,15 +2,16 @@
 
 namespace tecnocen\workflow\roa\resources;
 
-use Yii;
-use yii\web\NotFoundHttpException;
+use tecnocen\roa\controllers\Resource;
 use tecnocen\workflow\roa\models\Stage;
 use tecnocen\workflow\roa\models\StageSearch;
 
 /**
- * Resource to
+ * Resource to handle `Stage` records.
+ *
+ * @author Angel (Faryshta) Guevara <aguevara@alquimiadigital.mx>
  */
-class StageResource extends \tecnocen\roa\controllers\Resource
+class StageResource extends Resource
 {
     /**
      * @inheritdoc
diff --git a/src/roa/resources/TransitionResource.php b/src/roa/resources/TransitionResource.php
index 15477cd..4f69e74 100644
--- a/src/roa/resources/TransitionResource.php
+++ b/src/roa/resources/TransitionResource.php
@@ -2,16 +2,16 @@
 
 namespace tecnocen\workflow\roa\resources;
 
-use Yii;
+use tecnocen\roa\controllers\Resource;
 use tecnocen\workflow\roa\models\Transition;
 use tecnocen\workflow\roa\models\TransitionSearch;
 
 /**
- * Resource to handle transition records.
+ * Resource to handle `Transition` records.
  *
  * @author Angel (Faryshta) Guevara <aguevara@alquimiadigital.mx>
  */
-class TransitionResource extends \tecnocen\roa\controllers\Resource
+class TransitionResource extends Resource
 {
     /**
      * @inhertidoc
diff --git a/src/roa/resources/WorkflowResource.php b/src/roa/resources/WorkflowResource.php
index 752178b..ce2d282 100644
--- a/src/roa/resources/WorkflowResource.php
+++ b/src/roa/resources/WorkflowResource.php
@@ -2,14 +2,16 @@
 
 namespace tecnocen\workflow\roa\resources;
 
+use tecnocen\roa\controllers\Resource;
 use tecnocen\workflow\roa\models\Workflow;
 use tecnocen\workflow\roa\models\WorkflowSearch;
 
 /**
- * CRUD resource for `Workflow` records
+ * Resource to handle `Workflow` records
+ *
  * @author Angel (Faryshta) Guevara <aguevara@alquimiadigital.mx>
  */
-class WorkflowResource extends \tecnocen\roa\controllers\Resource
+class WorkflowResource extends Resource
 {
     /**
      * @inheritdoc
diff --git a/tests/_app/api/models/Credit.php b/tests/_app/api/models/Credit.php
index c65b5a2..d69ad2f 100644
--- a/tests/_app/api/models/Credit.php
+++ b/tests/_app/api/models/Credit.php
@@ -2,28 +2,31 @@
 
 namespace app\api\models;
 
+use app\models as base;
 use tecnocen\roa\hal\Contract;
 use tecnocen\roa\hal\ContractTrait;
-use yii\web\NotFoundHttpException;
 
 /**
  * ROA contract to handle credit records.
- *
- * @method string[] getSlugLinks()
- * @method string getSelfLink()
  */
-class Credit extends \app\models\Credit implements Contract
+class Credit extends base\Credit implements Contract
 {
     use ContractTrait {
         getLinks as getContractLinks;
     }
 
-    protected function assignmentClass()
+    /**
+     * @inheritdoc
+     */
+    protected function assignmentClass(): string
     {
         return CreditAssignment::class;
     }
 
-    protected function workLogClass()
+    /**
+     * @inheritdoc
+     */
+    protected function workLogClass(): string
     {
         return CreditWorklog::class;
     }
@@ -31,7 +34,7 @@ protected function workLogClass()
     /**
      * @inheritdoc
      */
-    public function slugBehaviorConfig()
+    protected function slugBehaviorConfig(): array
     {
         return [
             'resourceName' => 'credit',
diff --git a/tests/_app/api/models/CreditAssignment.php b/tests/_app/api/models/CreditAssignment.php
index 2579821..a67bc5f 100644
--- a/tests/_app/api/models/CreditAssignment.php
+++ b/tests/_app/api/models/CreditAssignment.php
@@ -2,33 +2,28 @@
 
 namespace app\api\models;
 
+use app\models as base;
 use tecnocen\roa\hal\Contract;
 use tecnocen\roa\hal\ContractTrait;
-use yii\web\NotFoundHttpException;
 
 /**
- * ROA contract to handle credit_worklog records.
- *
- * @method string[] getSlugLinks()
- * @method string getSelfLink()
+ * ROA contract to handle credit_assignment records.
  */
-class CreditAssignment extends \app\models\CreditAssignment implements Contract
+class CreditAssignment extends base\CreditAssignment implements Contract
 {
-    use ContractTrait {
-        getLinks as getContractLinks;
-    }
+    use ContractTrait;
 
     /**
      * @inheritdoc
      */
-    protected function processClass()
+    protected function processClass(): string
     {
         return Credit::class;
     }
     /**
      * @inheritdoc
      */
-    protected function slugBehaviorConfig()
+    protected function slugBehaviorConfig(): array
     {
         return [
             'resourceName' => 'assignment',
@@ -36,11 +31,4 @@ protected function slugBehaviorConfig()
             'idAttribute' => 'user_id'
         ];
     }
-    /**
-     * @inheritdoc
-     */
-    public function getLinks()
-    {
-        return $this->getSlugLinks();
-    }
 }
diff --git a/tests/_app/api/models/CreditSearch.php b/tests/_app/api/models/CreditSearch.php
index b80727c..1120a08 100644
--- a/tests/_app/api/models/CreditSearch.php
+++ b/tests/_app/api/models/CreditSearch.php
@@ -2,9 +2,10 @@
 
 namespace app\api\models;
 
+use tecnocen\roa\ResourceSearch;
 use yii\data\ActiveDataProvider;
 
-class CreditSearch extends Credit implements \tecnocen\roa\ResourceSearch
+class CreditSearch extends Credit implements ResourceSearch
 {
     /**
      * @inhertidoc
@@ -24,12 +25,15 @@ public function rules()
     /**
      * @inhertidoc
      */
-    public function search(array $params, $formName = '')
-    {
+    public function search(
+        array $params,
+        ?string $formName = ''
+    ): ?ActiveDataProvider {
         $this->load($params, $formName);
         if (!$this->validate()) {
             return null;
         }
+
         $class = get_parent_class();
         return new ActiveDataProvider([
             'query' => $class::find()->andFilterWhere([
diff --git a/tests/_app/api/models/CreditWorklog.php b/tests/_app/api/models/CreditWorklog.php
index b799a18..e47425e 100644
--- a/tests/_app/api/models/CreditWorklog.php
+++ b/tests/_app/api/models/CreditWorklog.php
@@ -2,26 +2,21 @@
 
 namespace app\api\models;
 
+use app\models as base;
 use tecnocen\roa\hal\Contract;
 use tecnocen\roa\hal\ContractTrait;
-use yii\web\NotFoundHttpException;
 
 /**
  * ROA contract to handle credit_worklog records.
- *
- * @method string[] getSlugLinks()
- * @method string getSelfLink()
  */
-class CreditWorklog extends \app\models\CreditWorklog implements Contract
+class CreditWorklog extends base\CreditWorklog implements Contract
 {
-    use ContractTrait {
-        getLinks as getContractLinks;
-    }
-    
+    use ContractTrait;
+
     /**
      * @inheritdoc
      */
-    protected function processClass()
+    protected function processClass(): string
     {
         return Credit::class;
     }
@@ -29,21 +24,11 @@ protected function processClass()
     /**
      * @inheritdoc
      */
-    public function slugBehaviorConfig()
+    protected function slugBehaviorConfig(): array
     {
         return [
             'resourceName' => 'worklog',
             'parentSlugRelation' => 'process'
         ];
     }
-
-    /**
-     * @inheritdoc
-     */
-    public function getLinks()
-    {
-        return array_merge($this->getContractLinks(), [
-            'creditWorklogs' => $this->getSelfLink() . '/worklog',
-        ]);
-    }
 }
diff --git a/tests/_app/api/modules/Version.php b/tests/_app/api/modules/Version.php
index e357c4c..b0cc0dc 100644
--- a/tests/_app/api/modules/Version.php
+++ b/tests/_app/api/modules/Version.php
@@ -2,9 +2,11 @@
 
 namespace app\api\modules;
 
-use app\api\resources\CreditResource;
-use app\api\resources\CreditWorklogResource;
-use app\api\resources\CreditAssignmentResource;
+use app\api\resources\{
+    CreditResource,
+    CreditWorklogResource,
+    CreditAssignmentResource
+};
 
 class Version extends \tecnocen\roa\modules\ApiVersion
 {
diff --git a/tests/_app/api/resources/CreditAssignmentResource.php b/tests/_app/api/resources/CreditAssignmentResource.php
index 224f8d8..3c8e375 100644
--- a/tests/_app/api/resources/CreditAssignmentResource.php
+++ b/tests/_app/api/resources/CreditAssignmentResource.php
@@ -2,15 +2,14 @@
 
 namespace app\api\resources;
 
-use Yii;
-use yii\web\NotFoundHttpException;
 use app\api\models\CreditAssignment;
+use tecnocen\roa\controllers\Resource;
 
 /**
  * CRUD resource for `Credit Assignment` records
  * @author Carlos (neverabe) Llamosas <carlos@tecnocen.com>
  */
-class CreditAssignmentResource extends \tecnocen\roa\controllers\Resource
+class CreditAssignmentResource extends Resource
 {
     /**
      * @inheritdoc
diff --git a/tests/_app/api/resources/CreditResource.php b/tests/_app/api/resources/CreditResource.php
index 569fcad..cf6b802 100644
--- a/tests/_app/api/resources/CreditResource.php
+++ b/tests/_app/api/resources/CreditResource.php
@@ -2,16 +2,15 @@
 
 namespace app\api\resources;
 
-use Yii;
-use yii\web\NotFoundHttpException;
 use app\api\models\Credit;
 use app\api\models\CreditSearch;
+use tecnocen\roa\controllers\Resource;
 
 /**
  * CRUD resource for `Credit` records
  * @author Carlos (neverabe) Llamosas <carlos@tecnocen.com>
  */
-class CreditResource extends \tecnocen\roa\controllers\Resource
+class CreditResource extends Resource
 {
     /**
      * @inheritdoc
diff --git a/tests/_app/api/resources/CreditWorklogResource.php b/tests/_app/api/resources/CreditWorklogResource.php
index 7fea2a8..652f414 100644
--- a/tests/_app/api/resources/CreditWorklogResource.php
+++ b/tests/_app/api/resources/CreditWorklogResource.php
@@ -2,15 +2,14 @@
 
 namespace app\api\resources;
 
-use Yii;
-use yii\web\NotFoundHttpException;
 use app\api\models\CreditWorklog;
+use tecnocen\roa\controllers\Resource;
 
 /**
  * CRUD resource for `Credit Worklog` records
  * @author Carlos (neverabe) Llamosas <carlos@tecnocen.com>
  */
-class CreditWorklogResource extends \tecnocen\roa\controllers\Resource
+class CreditWorklogResource extends Resource
 {
     /**
      * @inheritdoc
diff --git a/tests/_app/models/Credit.php b/tests/_app/models/Credit.php
index 243a4da..04535a1 100644
--- a/tests/_app/models/Credit.php
+++ b/tests/_app/models/Credit.php
@@ -21,17 +21,17 @@ public static function tableName()
         return '{{%credit}}';
     }
 
-    protected function assignmentClass()
+    protected function assignmentClass(): string
     {
         return CreditAssignment::class;
     }
 
-    protected function workLogClass()
+    protected function workLogClass():string
     {
         return CreditWorklog::class;
     }
 
-    public function getWorkflowId()
+    public function getWorkflowId(): int
     {
         return $this->workflow_id;
     }
diff --git a/tests/_app/models/CreditAssignment.php b/tests/_app/models/CreditAssignment.php
index ad74621..817ebab 100644
--- a/tests/_app/models/CreditAssignment.php
+++ b/tests/_app/models/CreditAssignment.php
@@ -4,11 +4,18 @@
 
 class CreditAssignment extends \tecnocen\workflow\models\Assignment
 {
+    /**
+     * @inheritdoc
+     */
     public static function tableName()
     {
         return '{{%credit_assignment}}';
     }
-    protected function processClass()
+ 
+    /**
+     * @inheritdoc
+     */
+   protected function processClass(): string
     {
         return Credit::class;
     }
diff --git a/tests/_app/models/CreditWorklog.php b/tests/_app/models/CreditWorklog.php
index bb8c6b9..8ef2fb2 100644
--- a/tests/_app/models/CreditWorklog.php
+++ b/tests/_app/models/CreditWorklog.php
@@ -9,7 +9,7 @@ public static function tableName()
         return '{{%credit_worklog}}';
     }
 
-    protected function processClass()
+    protected function processClass(): string
     {
         return Credit::class;
     }
diff --git a/tests/api/WorkflowCest.php b/tests/api/WorkflowCest.php
index 94c494a..0d64065 100644
--- a/tests/api/WorkflowCest.php
+++ b/tests/api/WorkflowCest.php
@@ -106,18 +106,20 @@ protected function viewDataProvider()
                         'stages' => [
                             ['id' => 1],
                         ],
+                        'totalStages' => 3,
                     ],
                 ],
             ],
             'field total stages' => [
                 'urlParams' => [
                     'id' => '1',
-                    'fields' => 'id,name,totalStages'
+                    'fields' => 'id,name'
                 ],
                 'httpCode' => HttpCode::OK,
                 'response' => [
-                    'totalStages' => 3,
-                ]
+                    'id' => 1,
+                    'name' => 'workflow 1',
+                ],
             ],
         ];
     }