[8.x] Add assertExists testing method

src/Illuminate/Foundation/Testing/Concerns/InteractsWithDatabase.php

@@ -108,6 +108,36 @@ protected function assertSoftDeleted($table, array $data = [], $connection = nul
         return $this;
     }
 
+    /**
+     * Assert the given model exists in the database.
+     *
+     * @param  \Illuminate\Database\Eloquent\Model  $model
+     * @return $this
+     */
+    protected function assertModelExists($model)
+    {
+        return $this->assertDatabaseHas(
+            $model->getTable(),
+            [$model->getKeyName() => $model->getKey()],
+            $model->getConnectionName()
+        );
+    }
+
+    /**
+     * Assert the given model does not exist in the database.
+     *
+     * @param  \Illuminate\Database\Eloquent\Model  $model
+     * @return $this
+     */
+    protected function assertModelMissing($model)
+    {
+        return $this->assertDatabaseMissing(
+            $model->getTable(),
+            [$model->getKeyName() => $model->getKey()],
+            $model->getConnectionName()
+        );
+    }
+
     /**
      * Determine if the argument is a soft deletable model.
      *

tests/Foundation/FoundationInteractsWithDatabaseTest.php

@@ -172,6 +172,17 @@ public function testAssertDeletedPassesWhenDoesNotFindModelResults()
         $this->assertDeleted(new ProductStub($this->data));
     }
 
+    public function testAssertModelMissingPassesWhenDoesNotFindModelResults()
+    {
+        $this->data = ['id' => 1];
+
+        $builder = $this->mockCountBuilder(0);
+
+        $builder->shouldReceive('get')->andReturn(collect());
+
+        $this->assertModelMissing(new ProductStub($this->data));
+    }
+
     public function testAssertDeletedFailsWhenFindsModelResults()
     {
         $this->expectException(ExpectationFailedException::class);
@@ -239,6 +250,17 @@ public function testAssertSoftDeletedInDatabaseDoesNotFindModelWithCustomColumnR
         $this->assertSoftDeleted(new CustomProductStub($this->data));
     }
 
+    public function testAssertExistsPassesWhenFindsResults()
+    {
+        $this->data = ['id' => 1];
+
+        $builder = $this->mockCountBuilder(1);
+
+        $builder->shouldReceive('get')->andReturn(collect($this->data));
+
+        $this->assertModelExists(new ProductStub($this->data));
+    }
+
     public function testGetTableNameFromModel()
     {
         $this->assertEquals($this->table, $this->getTable(ProductStub::class));