How to check if row is soft-deleted in Eloquent?

This is the best way

$model = 'App\\Models\\ModelName';

$uses_soft_delete = in_array('Illuminate\Database\Eloquent\SoftDeletes', class_uses($model));

if($usesSoftDeletes) {
    // write code...
}

In laravel6, you can use followings.

To check the Eloquent Model is using soft delete:

if( method_exists($thing, 'trashed') ) {
    // do something
}

To check the Eloquent Model is using soft delete in resource (when using resource to response):

if( method_exists($this->resource, 'trashed') ) {
    // do something
}

And finally to check if the model is trashed:

if ($thing->trashed()) {
    // do something
}

Hope, this will be helpful!

For those seeking an answer on testing environment, within laravel's test case you can assert as:

$this->assertSoftDeleted($user);

or in case it's just deleted (without soft deleting)

$this->assertDeleted($user);

Just realised I was looking in the wrong API. The Model class doesn't have this, but the SoftDelete trait that my models use has a trashed() method.

So I can write

if ($thing->trashed()) { ... }