add a file hash driver

Author: SjorsO

.gitignore

@@ -2,3 +2,4 @@ build
 composer.lock
 docs
 vendor
+.idea

README.md

@@ -86,11 +86,12 @@ composer require spatie/phpunit-snapshot-assertions
 
 ## Usage
 
-To make snapshot assertions, use the `Spatie\Snapshots\MatchesSnapshots` trait in your test case class. This adds three assertion methods to the class:
+To make snapshot assertions, use the `Spatie\Snapshots\MatchesSnapshots` trait in your test case class. This adds four assertion methods to the class:
 
 - `assertMatchesSnapshot($actual)`
 - `assertMatchesJsonSnapshot($actual)`
 - `assertMatchesXmlSnapshot($actual)`
+- `assertMatchesFileHashSnapshot($filePath)`
 
 ### Snapshot Testing 101
 

src/Drivers/FileHashDriver.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace Spatie\Snapshots\Drivers;
+
+use Exception;
+use PHPUnit\Framework\Assert;
+use Spatie\Snapshots\Driver;
+
+class FileHashDriver implements Driver
+{
+    public function serialize($data): string
+    {
+        if (! file_exists($data)) {
+            throw new Exception('File does not exist');
+        }
+
+        return sha1_file($data);
+    }
+
+    public function extension(): string
+    {
+        return 'txt';
+    }
+
+    public function match($expected, $actual)
+    {
+        Assert::assertSame($expected, $actual);
+    }
+}

src/MatchesSnapshots.php

@@ -2,10 +2,12 @@
 
 namespace Spatie\Snapshots;
 
+use Exception;
 use PHPUnit\Framework\ExpectationFailedException;
 use PHPUnit_Framework_ExpectationFailedException;
 use ReflectionClass;
 use ReflectionObject;
+use Spatie\Snapshots\Drivers\FileHashDriver;
 use Spatie\Snapshots\Drivers\JsonDriver;
 use Spatie\Snapshots\Drivers\VarDriver;
 use Spatie\Snapshots\Drivers\XmlDriver;
@@ -36,6 +38,17 @@ public function assertMatchesJsonSnapshot($actual)
         $this->assertMatchesSnapshot($actual, new JsonDriver());
     }
 
+    public function assertMatchesFileHashSnapshot($filePath)
+    {
+        if (! file_exists($filePath)) {
+            throw new Exception('File does not exist');
+        }
+
+        $actual = sha1_file($filePath);
+
+        $this->assertMatchesSnapshot($actual, new FileHashDriver());
+    }
+
     /**
      * Determines the snapshot's id. By default, the test case's class and
      * method names are used.

tests/Integration/AssertionTest.php

@@ -41,6 +41,14 @@ public function can_match_a_json_snapshot()
         $this->assertMatchesJsonSnapshot($data);
     }
 
+    /** @test */
+    public function can_match_a_file_hash_snapshot()
+    {
+        $filePath = __DIR__ . '/stubs/example_snapshots/snapshot.json';
+
+        $this->assertMatchesFileHashSnapshot($filePath);
+    }
+
     /** @test */
     public function can_do_multiple_snapshot_assertions()
     {

tests/Integration/stubs/__snapshots__/AssertionTest__can_match_a_file_hash_snapshot__1.txt

@@ -0,0 +1 @@
+f558f8149e33fba2916877b2d3de4a42ebd544b4

tests/Unit/Drivers/FileHashDriverTest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace Spatie\Snapshots\Test\Unit\Drivers;
+
+use Exception;
+use PHPUnit\Framework\TestCase;
+use Spatie\Snapshots\Drivers\FileHashDriver;
+
+class FileHashDriverTest extends TestCase
+{
+    /** @test */
+    public function it_can_hash_a_file()
+    {
+        $driver = new FileHashDriver();
+
+        $filePath = __DIR__ . '/files/example-file.txt';
+
+        $expected = sha1_file($filePath);
+
+        $this->assertEquals($expected, $driver->serialize($filePath));
+    }
+
+    /** @test */
+    public function it_throws_an_exception_if_the_file_does_not_exist()
+    {
+        $driver = new FileHashDriver();
+
+        $this->expectException(Exception::class);
+
+        $driver->serialize(__DIR__ . '/files/fake-file-path');
+    }
+}

tests/Unit/Drivers/files/example-file.txt

@@ -0,0 +1,3 @@
+Spatie is a digital allrounder:
+we design solid websites and crafty applications in Laravel.
+No frills, just expertise.