3 files changed, 60 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index f34ecf9d..db95e88b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -37,6 +37,7 @@ Bug fixes:
 * Fix wrong link for category in task footer
 * Unable to set currency rate with Postgres database
 * Avoid automatic actions that change the color to fire subsequent events
+* Unable to unassign a task from the API
 
 Version 1.0.23
 --------------
diff --git a/app/Api/Task.php b/app/Api/Task.php
index 1491cd35..97d89775 100644
--- a/app/Api/Task.php
+++ b/app/Api/Task.php
@@ -117,7 +117,7 @@ class Task extends Base
             return false;
         }
 
-        if ($owner_id !== null && ! $this->projectPermission->isAssignable($project_id, $owner_id)) {
+        if ($owner_id !== null && $owner_id != 0 && ! $this->projectPermission->isAssignable($project_id, $owner_id)) {
             return false;
         }
 
diff --git a/tests/integration/TaskTest.php b/tests/integration/TaskTest.php
new file mode 100644
index 00000000..20da12bd
--- /dev/null
+++ b/tests/integration/TaskTest.php
@@ -0,0 +1,58 @@
+<?php
+
+require_once __DIR__.'/Base.php';
+
+class TaskTest extends Base
+{
+    public function testChangeAssigneeToAssignableUser()
+    {
+        $project_id = $this->app->createProject('My project');
+        $this->assertNotFalse($project_id);
+
+        $user_id = $this->app->createUser('user0', 'password');
+        $this->assertNotFalse($user_id);
+
+        $this->assertTrue($this->app->addProjectUser($project_id, $user_id, 'project-member'));
+
+        $task_id = $this->app->createTask(array('project_id' => $project_id, 'title' => 'My task'));
+        $this->assertNotFalse($task_id);
+
+        $this->assertTrue($this->app->updateTask(array('id' => $task_id, 'project_id' => $project_id, 'owner_id' => $user_id)));
+
+        $task = $this->app->getTask($task_id);
+        $this->assertEquals($user_id, $task['owner_id']);
+    }
+
+    public function testChangeAssigneeToNotAssignableUser()
+    {
+        $project_id = $this->app->createProject('My project');
+        $this->assertNotFalse($project_id);
+
+        $task_id = $this->app->createTask(array('project_id' => $project_id, 'title' => 'My task'));
+        $this->assertNotFalse($task_id);
+
+        $this->assertFalse($this->app->updateTask(array('id' => $task_id, 'project_id' => $project_id, 'owner_id' => 1)));
+
+        $task = $this->app->getTask($task_id);
+        $this->assertEquals(0, $task['owner_id']);
+    }
+
+    public function testChangeAssigneeToNobody()
+    {
+        $project_id = $this->app->createProject('My project');
+        $this->assertNotFalse($project_id);
+
+        $user_id = $this->app->createUser('user1', 'password');
+        $this->assertNotFalse($user_id);
+
+        $this->assertTrue($this->app->addProjectUser($project_id, $user_id, 'project-member'));
+
+        $task_id = $this->app->createTask(array('project_id' => $project_id, 'title' => 'My task', 'owner_id' => $user_id));
+        $this->assertNotFalse($task_id);
+
+        $this->assertTrue($this->app->updateTask(array('id' => $task_id, 'project_id' => $project_id, 'owner_id' => 0)));
+
+        $task = $this->app->getTask($task_id);
+        $this->assertEquals(0, $task['owner_id']);
+    }
+}