Added search filter for task priority

tests/units/Filter/TaskPriorityFilterTest.php

@@ -0,0 +1,47 @@
+<?php
+
+use Kanboard\Filter\TaskPriorityFilter;
+use Kanboard\Model\ProjectModel;
+use Kanboard\Model\TaskCreationModel;
+use Kanboard\Model\TaskFinderModel;
+
+require_once __DIR__.'/../Base.php';
+
+class TaskPriorityFilterTest extends Base
+{
+    public function testWithDefinedPriority()
+    {
+        $taskFinder = new TaskFinderModel($this->container);
+        $taskCreation = new TaskCreationModel($this->container);
+        $projectModel = new ProjectModel($this->container);
+        $query = $taskFinder->getExtendedQuery();
+
+        $this->assertEquals(1, $projectModel->create(array('name' => 'Test')));
+        $this->assertEquals(1, $taskCreation->create(array('title' => 'Test', 'project_id' => 1, 'priority' => 2)));
+
+        $filter = new TaskPriorityFilter();
+        $filter->withQuery($query);
+        $filter->withValue(2);
+        $filter->apply();
+
+        $this->assertCount(1, $query->findAll());
+    }
+
+    public function testWithNoPriority()
+    {
+        $taskFinder = new TaskFinderModel($this->container);
+        $taskCreation = new TaskCreationModel($this->container);
+        $projectModel = new ProjectModel($this->container);
+        $query = $taskFinder->getExtendedQuery();
+
+        $this->assertEquals(1, $projectModel->create(array('name' => 'Test')));
+        $this->assertEquals(1, $taskCreation->create(array('title' => 'Test', 'project_id' => 1)));
+
+        $filter = new TaskPriorityFilter();
+        $filter->withQuery($query);
+        $filter->withValue(2);
+        $filter->apply();
+
+        $this->assertCount(0, $query->findAll());
+    }
+}