From a479073b16ff294ab5b91e284e8cc89f3266d1ca Mon Sep 17 00:00:00 2001
From: Christopher Gammie <cgammie@sirran.com>
Date: Fri, 27 Sep 2019 10:16:22 +0100
Subject: [PATCH 1/3] Add has-one-through relationship

---
 src/Eloquent/AbstractAdapter.php              |   9 ++
 src/Eloquent/HasOneThrough.php                |  50 +++++++++
 tests/dummy/app/History.php                   |  23 ++++
 tests/dummy/app/JsonApi/Histories/Adapter.php |  43 +++++++
 tests/dummy/app/JsonApi/Histories/Schema.php  |  55 +++++++++
 .../app/JsonApi/Histories/Validators.php      |  56 +++++++++
 tests/dummy/app/JsonApi/Suppliers/Adapter.php |  52 +++++++++
 tests/dummy/app/JsonApi/Suppliers/Schema.php  |  70 ++++++++++++
 .../app/JsonApi/Suppliers/Validators.php      |  56 +++++++++
 tests/dummy/app/Supplier.php                  |  23 ++++
 tests/dummy/app/User.php                      |   8 ++
 tests/dummy/config/json-api-v1.php            |   2 +
 .../dummy/database/factories/ModelFactory.php |  17 +++
 .../2018_02_11_1648_create_tables.php         |  16 +++
 tests/dummy/routes/api.php                    |   6 +
 .../Eloquent/HasManyThroughTest.php           |   4 +-
 .../Eloquent/HasOneThroughTest.php            | 106 ++++++++++++++++++
 17 files changed, 594 insertions(+), 2 deletions(-)
 create mode 100644 src/Eloquent/HasOneThrough.php
 create mode 100644 tests/dummy/app/History.php
 create mode 100644 tests/dummy/app/JsonApi/Histories/Adapter.php
 create mode 100644 tests/dummy/app/JsonApi/Histories/Schema.php
 create mode 100644 tests/dummy/app/JsonApi/Histories/Validators.php
 create mode 100644 tests/dummy/app/JsonApi/Suppliers/Adapter.php
 create mode 100644 tests/dummy/app/JsonApi/Suppliers/Schema.php
 create mode 100644 tests/dummy/app/JsonApi/Suppliers/Validators.php
 create mode 100644 tests/dummy/app/Supplier.php
 create mode 100644 tests/lib/Integration/Eloquent/HasOneThroughTest.php

diff --git a/src/Eloquent/AbstractAdapter.php b/src/Eloquent/AbstractAdapter.php
index d24d1c47..c825124b 100644
--- a/src/Eloquent/AbstractAdapter.php
+++ b/src/Eloquent/AbstractAdapter.php
@@ -555,6 +555,15 @@ protected function hasOne($modelKey = null)
         return new HasOne($modelKey ?: $this->guessRelation());
     }
 
+    /**
+     * @param string|null $modelKey
+     * @return HasOneThrough
+     */
+    protected function hasOneThrough($modelKey = null)
+    {
+        return new HasOneThrough($modelKey ?: $this->guessRelation());
+    }
+
     /**
      * @param string|null $modelKey
      * @return HasMany
diff --git a/src/Eloquent/HasOneThrough.php b/src/Eloquent/HasOneThrough.php
new file mode 100644
index 00000000..335b0e3e
--- /dev/null
+++ b/src/Eloquent/HasOneThrough.php
@@ -0,0 +1,50 @@
+<?php
+/**
+ * Copyright 2019 Cloud Creativity Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace CloudCreativity\LaravelJsonApi\Eloquent;
+
+use CloudCreativity\LaravelJsonApi\Exceptions\RuntimeException;
+use Illuminate\Database\Eloquent\Relations;
+use Neomerx\JsonApi\Contracts\Encoder\Parameters\EncodingParametersInterface;
+
+class HasOneThrough extends BelongsTo
+{
+
+    /**
+     * @inheritDoc
+     */
+    public function update($record, array $relationship, EncodingParametersInterface $parameters)
+    {
+        throw new RuntimeException('Modifying a has-one-through Eloquent relation is not supported.');
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function replace($record, array $relationship, EncodingParametersInterface $parameters)
+    {
+        throw new RuntimeException('Modifying a has-one-through Eloquent relation is not supported.');
+    }
+
+    /**
+     * @inheritdoc
+     */
+    protected function acceptRelation($relation)
+    {
+        return $relation instanceof Relations\HasOneThrough;
+    }
+}
diff --git a/tests/dummy/app/History.php b/tests/dummy/app/History.php
new file mode 100644
index 00000000..38a6c44d
--- /dev/null
+++ b/tests/dummy/app/History.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace DummyApp;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class History extends Model
+{
+
+    /**
+     * @var array
+     */
+    protected $fillable = ['detail'];
+
+    /**
+     * @return BelongsTo
+     */
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+}
diff --git a/tests/dummy/app/JsonApi/Histories/Adapter.php b/tests/dummy/app/JsonApi/Histories/Adapter.php
new file mode 100644
index 00000000..6eab2e62
--- /dev/null
+++ b/tests/dummy/app/JsonApi/Histories/Adapter.php
@@ -0,0 +1,43 @@
+<?php
+/**
+ * Copyright 2019 Cloud Creativity Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace DummyApp\JsonApi\Histories;
+
+use CloudCreativity\LaravelJsonApi\Eloquent\AbstractAdapter;
+use DummyApp\History;
+use Illuminate\Support\Collection;
+
+class Adapter extends AbstractAdapter
+{
+
+    /**
+     * Adapter constructor.
+     */
+    public function __construct()
+    {
+        parent::__construct(new History());
+    }
+
+    /**
+     * @inheritDoc
+     */
+    protected function filter($query, Collection $filters)
+    {
+        // TODO: Implement filter() method.
+    }
+
+}
diff --git a/tests/dummy/app/JsonApi/Histories/Schema.php b/tests/dummy/app/JsonApi/Histories/Schema.php
new file mode 100644
index 00000000..a474303f
--- /dev/null
+++ b/tests/dummy/app/JsonApi/Histories/Schema.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace DummyApp\JsonApi\Histories;
+
+use DummyApp\History;
+use Neomerx\JsonApi\Schema\SchemaProvider;
+
+class Schema extends SchemaProvider
+{
+
+    /**
+     * @var string
+     */
+    protected $resourceType = 'histories';
+
+    /**
+     * @param History $resource
+     * @return string
+     */
+    public function getId($resource)
+    {
+        return (string) $resource->getRouteKey();
+    }
+
+    /**
+     * @param History $resource
+     * @return array
+     */
+    public function getAttributes($resource)
+    {
+        return ['detail' => $resource->detail];
+    }
+
+    /**
+     * @param History $resource
+     * @param bool $isPrimary
+     * @param array $includeRelationships
+     * @return array
+     */
+    public function getRelationships($resource, $isPrimary, array $includeRelationships)
+    {
+        return [
+            'user' => [
+                self::SHOW_SELF => false,
+                self::SHOW_RELATED => false,
+                self::SHOW_DATA => isset($includeRelationships['user']),
+                self::DATA => static function () use ($resource) {
+                    return $resource->user;
+                },
+            ],
+        ];
+    }
+
+
+}
diff --git a/tests/dummy/app/JsonApi/Histories/Validators.php b/tests/dummy/app/JsonApi/Histories/Validators.php
new file mode 100644
index 00000000..338d358c
--- /dev/null
+++ b/tests/dummy/app/JsonApi/Histories/Validators.php
@@ -0,0 +1,56 @@
+<?php
+/**
+ * Copyright 2019 Cloud Creativity Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace DummyApp\JsonApi\Histories;
+
+use CloudCreativity\LaravelJsonApi\Validation\AbstractValidators;
+
+class Validators extends AbstractValidators
+{
+
+    /**
+     * @var array
+     */
+    protected $allowedIncludePaths = ['user'];
+
+    /**
+     * @var array
+     */
+    protected $allowedSortParameters = [
+        'created-at',
+        'updated-at',
+    ];
+
+    /**
+     * @inheritDoc
+     */
+    protected function rules($record = null): array
+    {
+        return [
+            'detail' => ['required', 'string'],
+        ];
+    }
+
+    /**
+     * @inheritDoc
+     */
+    protected function queryRules(): array
+    {
+        return [];
+    }
+
+}
diff --git a/tests/dummy/app/JsonApi/Suppliers/Adapter.php b/tests/dummy/app/JsonApi/Suppliers/Adapter.php
new file mode 100644
index 00000000..45ae38e7
--- /dev/null
+++ b/tests/dummy/app/JsonApi/Suppliers/Adapter.php
@@ -0,0 +1,52 @@
+<?php
+/**
+ * Copyright 2019 Cloud Creativity Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace DummyApp\JsonApi\Suppliers;
+
+use CloudCreativity\LaravelJsonApi\Eloquent\AbstractAdapter;
+use CloudCreativity\LaravelJsonApi\Eloquent\HasOneThrough;
+use DummyApp\Supplier;
+use Illuminate\Support\Collection;
+
+class Adapter extends AbstractAdapter
+{
+
+    /**
+     * Adapter constructor.
+     */
+    public function __construct()
+    {
+        parent::__construct(new Supplier());
+    }
+
+    /**
+     * @return HasOneThrough
+     */
+    protected function userHistory(): HasOneThrough
+    {
+        return $this->hasOneThrough();
+    }
+
+    /**
+     * @inheritDoc
+     */
+    protected function filter($query, Collection $filters)
+    {
+        // TODO: Implement filter() method.
+    }
+
+}
diff --git a/tests/dummy/app/JsonApi/Suppliers/Schema.php b/tests/dummy/app/JsonApi/Suppliers/Schema.php
new file mode 100644
index 00000000..550137bf
--- /dev/null
+++ b/tests/dummy/app/JsonApi/Suppliers/Schema.php
@@ -0,0 +1,70 @@
+<?php
+/**
+ * Copyright 2019 Cloud Creativity Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace DummyApp\JsonApi\Suppliers;
+
+use DummyApp\Supplier;
+use Neomerx\JsonApi\Schema\SchemaProvider;
+
+class Schema extends SchemaProvider
+{
+
+    /**
+     * @var string
+     */
+    protected $resourceType = 'suppliers';
+
+    /**
+     * @param Supplier $resource
+     * @return string
+     */
+    public function getId($resource)
+    {
+        return (string) $resource->getRouteKey();
+    }
+
+    /**
+     * @param Supplier $resource
+     * @return array
+     */
+    public function getAttributes($resource)
+    {
+        return ['name' => $resource->name];
+    }
+
+    /**
+     * @param Supplier $resource
+     * @param bool $isPrimary
+     * @param array $includeRelationships
+     * @return array
+     */
+    public function getRelationships($resource, $isPrimary, array $includeRelationships)
+    {
+        return [
+            'user-history' => [
+                self::SHOW_SELF => true,
+                self::SHOW_RELATED => true,
+                self::SHOW_DATA => isset($includeRelationships['user-history']),
+                self::DATA => static function () use ($resource) {
+                    return $resource->userHistory;
+                },
+            ],
+        ];
+    }
+
+
+}
diff --git a/tests/dummy/app/JsonApi/Suppliers/Validators.php b/tests/dummy/app/JsonApi/Suppliers/Validators.php
new file mode 100644
index 00000000..566b368c
--- /dev/null
+++ b/tests/dummy/app/JsonApi/Suppliers/Validators.php
@@ -0,0 +1,56 @@
+<?php
+/**
+ * Copyright 2019 Cloud Creativity Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace DummyApp\JsonApi\Suppliers;
+
+use CloudCreativity\LaravelJsonApi\Validation\AbstractValidators;
+
+class Validators extends AbstractValidators
+{
+
+    /**
+     * @var array
+     */
+    protected $allowedIncludePaths = ['user-history'];
+
+    /**
+     * @var array
+     */
+    protected $allowedSortParameters = [
+        'created-at',
+        'updated-at',
+    ];
+
+    /**
+     * @inheritDoc
+     */
+    protected function rules($record = null): array
+    {
+        return [
+            'name' => ['required', 'string'],
+        ];
+    }
+
+    /**
+     * @inheritDoc
+     */
+    protected function queryRules(): array
+    {
+        return [];
+    }
+
+}
diff --git a/tests/dummy/app/Supplier.php b/tests/dummy/app/Supplier.php
new file mode 100644
index 00000000..747cb1d7
--- /dev/null
+++ b/tests/dummy/app/Supplier.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace DummyApp;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasOneThrough;
+
+class Supplier extends Model
+{
+
+    /**
+     * @var array
+     */
+    protected $fillable = ['name'];
+
+    /**
+     * @return HasOneThrough
+     */
+    public function userHistory(): HasOneThrough
+    {
+        return $this->hasOneThrough(History::class, User::class);
+    }
+}
diff --git a/tests/dummy/app/User.php b/tests/dummy/app/User.php
index 9b3856ab..c8256d08 100644
--- a/tests/dummy/app/User.php
+++ b/tests/dummy/app/User.php
@@ -80,4 +80,12 @@ public function country()
     {
         return $this->belongsTo(Country::class);
     }
+
+    /**
+     * @return BelongsTo
+     */
+    public function supplier()
+    {
+        return $this->belongsTo(Supplier::class);
+    }
 }
diff --git a/tests/dummy/config/json-api-v1.php b/tests/dummy/config/json-api-v1.php
index b1ed4147..f1b1e5e7 100644
--- a/tests/dummy/config/json-api-v1.php
+++ b/tests/dummy/config/json-api-v1.php
@@ -57,9 +57,11 @@
         'comments' => \DummyApp\Comment::class,
         'countries' => \DummyApp\Country::class,
         'downloads' => \DummyApp\Download::class,
+        'histories' => \DummyApp\History::class,
         'phones' => \DummyApp\Phone::class,
         'posts' => \DummyApp\Post::class,
         'sites' => \DummyApp\Entities\Site::class,
+        'suppliers' => \DummyApp\Supplier::class,
         'tags' => \DummyApp\Tag::class,
         'users' => \DummyApp\User::class,
         'videos' => \DummyApp\Video::class,
diff --git a/tests/dummy/database/factories/ModelFactory.php b/tests/dummy/database/factories/ModelFactory.php
index 872c5e20..47beb032 100644
--- a/tests/dummy/database/factories/ModelFactory.php
+++ b/tests/dummy/database/factories/ModelFactory.php
@@ -145,3 +145,20 @@
         },
     ];
 });
+
+/** Supplier */
+$factory->define(DummyApp\Supplier::class, function (Faker $faker) {
+    return [
+        'name' => $faker->company,
+    ];
+});
+
+/** History */
+$factory->define(DummyApp\History::class, function (Faker $faker) {
+    return [
+        'detail' => $faker->paragraph,
+        'user_id' => function () {
+            return factory(DummyApp\User::class)->create()->getKey();
+        },
+    ];
+});
diff --git a/tests/dummy/database/migrations/2018_02_11_1648_create_tables.php b/tests/dummy/database/migrations/2018_02_11_1648_create_tables.php
index 553bbade..23267f37 100644
--- a/tests/dummy/database/migrations/2018_02_11_1648_create_tables.php
+++ b/tests/dummy/database/migrations/2018_02_11_1648_create_tables.php
@@ -37,6 +37,7 @@ public function up()
             $table->rememberToken();
             $table->timestamps();
             $table->unsignedInteger('country_id')->nullable();
+            $table->unsignedInteger('supplier_id')->nullable();
         });
 
         Schema::create('avatars', function (Blueprint $table) {
@@ -107,6 +108,19 @@ public function up()
             $table->timestamps();
             $table->string('category');
         });
+
+        Schema::create('suppliers', function (Blueprint $table) {
+            $table->increments('id');
+            $table->timestamps();
+            $table->string('name');
+        });
+
+        Schema::create('histories', function (Blueprint $table) {
+            $table->increments('id');
+            $table->timestamps();
+            $table->text('detail');
+            $table->unsignedInteger('user_id');
+        });
     }
 
     /**
@@ -122,5 +136,7 @@ public function down()
         Schema::dropIfExists('phones');
         Schema::dropIfExists('countries');
         Schema::dropIfExists('downloads');
+        Schema::dropIfExists('suppliers');
+        Schema::dropIfExists('histories');
     }
 }
diff --git a/tests/dummy/routes/api.php b/tests/dummy/routes/api.php
index 41d12bc2..0f0ab7e5 100644
--- a/tests/dummy/routes/api.php
+++ b/tests/dummy/routes/api.php
@@ -62,4 +62,10 @@
     $api->resource('sites', [
         'controller' => true,
     ]);
+
+    $api->resource('suppliers', [
+        'has-one' => [
+            'user-history' => ['only' => ['read', 'related']],
+        ],
+    ]);
 });
diff --git a/tests/lib/Integration/Eloquent/HasManyThroughTest.php b/tests/lib/Integration/Eloquent/HasManyThroughTest.php
index d19904b7..fd2c6950 100644
--- a/tests/lib/Integration/Eloquent/HasManyThroughTest.php
+++ b/tests/lib/Integration/Eloquent/HasManyThroughTest.php
@@ -23,9 +23,9 @@
 use DummyApp\User;
 
 /**
- * Class HasManyTest
+ * Class HasManyThroughTest
  *
- * Test a JSON API has-many relationship that relates to an Eloquent
+ * Test a JSON API has-many-through relationship that relates to an Eloquent
  * has-many-through relationship.
  *
  * In our dummy app, this is the posts relationship on a country model.
diff --git a/tests/lib/Integration/Eloquent/HasOneThroughTest.php b/tests/lib/Integration/Eloquent/HasOneThroughTest.php
new file mode 100644
index 00000000..b6b0e4ba
--- /dev/null
+++ b/tests/lib/Integration/Eloquent/HasOneThroughTest.php
@@ -0,0 +1,106 @@
+<?php
+/**
+ * Copyright 2019 Cloud Creativity Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace CloudCreativity\LaravelJsonApi\Tests\Integration\Eloquent;
+
+use CloudCreativity\LaravelJsonApi\Tests\Integration\TestCase;
+use DummyApp\History;
+use DummyApp\Supplier;
+use DummyApp\User;
+
+/**
+ * Class HasOneThroughTest
+ *
+ * Test a JSON API has-one-through relationship that relates to an Eloquent
+ * has-one-through relationship.
+ *
+ * In our dummy app, this is the user-history relationship on a supplier model.
+ *
+ * This relationship is read-only because it does not make sense to
+ * modify the relationship through the resource relationship. I.e. the
+ * history resource would be created/modified etc.
+ *
+ * @package CloudCreativity\LaravelJsonApi
+ */
+class HasOneThroughTest extends TestCase
+{
+
+    /**
+     * @var string
+     */
+    protected $resourceType = 'suppliers';
+
+    /**
+     * Test that we can read the related phone.
+     */
+    public function testReadRelated(): void
+    {
+        $supplier = factory(Supplier::class)->create();
+        $user = factory(User::class)->create(['supplier_id' => $supplier->getKey()]);
+        $history = factory(History::class)->create(['user_id' => $user->getKey()]);
+
+        $data = [
+            'type' => 'histories',
+            'id' => (string) $history->getRouteKey(),
+            'attributes' => [
+                'detail' => $history->detail,
+            ],
+            'relationships' => [
+                'user' => [
+                    'data' => [
+                        'type' => 'users',
+                        'id' => (string) $user->getRouteKey(),
+                    ],
+                ],
+            ],
+        ];
+
+        $this->withoutExceptionHandling()
+            ->doReadRelated($supplier, 'user-history', ['include' => 'user'])
+            ->assertFetchedOne($data);
+    }
+
+    public function testReadRelatedEmpty(): void
+    {
+        $supplier = factory(Supplier::class)->create();
+
+        $this->withoutExceptionHandling()
+            ->doReadRelated($supplier, 'user-history')
+            ->assertFetchedNull();
+    }
+
+    public function testReadRelationship(): void
+    {
+        $supplier = factory(Supplier::class)->create();
+        $user = factory(User::class)->create(['supplier_id' => $supplier->getKey()]);
+        $history = factory(History::class)->create(['user_id' => $user->getKey()]);
+
+        $this->withoutExceptionHandling()
+            ->willSeeResourceType('histories')
+            ->doReadRelationship($supplier, 'user-history')
+            ->assertFetchedToOne($history);
+    }
+
+    public function testReadEmptyRelationship(): void
+    {
+        $supplier = factory(Supplier::class)->create();
+
+        $this->withoutExceptionHandling()
+            ->doReadRelationship($supplier, 'user-history')
+            ->assertFetchedNull();
+    }
+}

From 9581748070298bca3ec5464dec2ad6f000ea7348 Mon Sep 17 00:00:00 2001
From: Christopher Gammie <cgammie@sirran.com>
Date: Fri, 27 Sep 2019 10:31:40 +0100
Subject: [PATCH 2/3] Skip tests for older versions of Laravel

---
 .../Eloquent/HasOneThroughTest.php            | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tests/lib/Integration/Eloquent/HasOneThroughTest.php b/tests/lib/Integration/Eloquent/HasOneThroughTest.php
index b6b0e4ba..a90e15ff 100644
--- a/tests/lib/Integration/Eloquent/HasOneThroughTest.php
+++ b/tests/lib/Integration/Eloquent/HasOneThroughTest.php
@@ -21,6 +21,7 @@
 use DummyApp\History;
 use DummyApp\Supplier;
 use DummyApp\User;
+use Illuminate\Database\Eloquent\Relations\HasOneThrough;
 
 /**
  * Class HasOneThroughTest
@@ -49,6 +50,8 @@ class HasOneThroughTest extends TestCase
      */
     public function testReadRelated(): void
     {
+        $this->checkSupported();
+
         $supplier = factory(Supplier::class)->create();
         $user = factory(User::class)->create(['supplier_id' => $supplier->getKey()]);
         $history = factory(History::class)->create(['user_id' => $user->getKey()]);
@@ -76,6 +79,8 @@ public function testReadRelated(): void
 
     public function testReadRelatedEmpty(): void
     {
+        $this->checkSupported();
+
         $supplier = factory(Supplier::class)->create();
 
         $this->withoutExceptionHandling()
@@ -85,6 +90,8 @@ public function testReadRelatedEmpty(): void
 
     public function testReadRelationship(): void
     {
+        $this->checkSupported();
+
         $supplier = factory(Supplier::class)->create();
         $user = factory(User::class)->create(['supplier_id' => $supplier->getKey()]);
         $history = factory(History::class)->create(['user_id' => $user->getKey()]);
@@ -97,10 +104,23 @@ public function testReadRelationship(): void
 
     public function testReadEmptyRelationship(): void
     {
+        $this->checkSupported();
+
         $supplier = factory(Supplier::class)->create();
 
         $this->withoutExceptionHandling()
             ->doReadRelationship($supplier, 'user-history')
             ->assertFetchedNull();
     }
+
+    /**
+     * @return void
+     * @todo remove when minimum Laravel version is 5.8.
+     */
+    private function checkSupported(): void
+    {
+        if (!class_exists(HasOneThrough::class)) {
+            $this->markTestSkipped('Eloquent has-one-through not supported.');
+        }
+    }
 }

From 4c032df18e4bd2ea4f298200912d0a1519b609fa Mon Sep 17 00:00:00 2001
From: Christopher Gammie <cgammie@sirran.com>
Date: Fri, 27 Sep 2019 10:35:48 +0100
Subject: [PATCH 3/3] Update docs

---
 docs/basics/adapters.md | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/docs/basics/adapters.md b/docs/basics/adapters.md
index 34fe6998..69489bd1 100644
--- a/docs/basics/adapters.md
+++ b/docs/basics/adapters.md
@@ -224,6 +224,7 @@ for Eloquent models. The relationship types available are `belongsTo`, `hasOne`,
 | Eloquent | JSON API |
 | :-- | :-- |
 | `hasOne` | `hasOne` |
+| `hasOneThrough` | `hasOneThrough` |
 | `belongsTo` | `belongsTo` |
 | `hasMany` | `hasMany` |
 | `belongsToMany` | `hasMany` |
@@ -338,15 +339,16 @@ class Adapter extends AbstractAdapter
 }
 ```
 
-#### Has-Many-Through
+#### Has-One-Through and Has-Many-Through
 
-The JSON API `hasManyThrough` relation can be used for an Eloquent `hasManyThrough` relation. The important thing
-to note about this relationship is it is **read-only**. This is because the relationship can be modified in your API
-by modifying the intermediary model. For example, a `countries` resource might have many `posts` resources through
-an intermediate `users` resource. The relationship is effectively modified by creating and deleting posts and/or a
-user changing which country they are associated to.
+The JSON API `hasOneThrough` and `hasManyThrough` relations can be used for an Eloquent `hasOneThrough`
+and `hasManyThrough` relation. The important thing to note about these relationships is that both are **read-only**.
+This is because the relationship can be modified in your API by modifying the intermediary model.
+For example, a `countries` resource might have many `posts` resources through an intermediate `users` resource.
+The relationship is effectively modified by creating and deleting posts and/or a user changing which country they
+are associated to.
 
-Define a has-many-through relationship on an adapter as follows:
+Use the `hasOneThrough()` or `hasManyThrough()` methods on your adapter as follows:
 
 ```php
 class Adapter extends AbstractAdapter