PHP8 (#20)

composer.json

@@ -15,10 +15,10 @@
         }
     ],
     "require": {
-        "php": "^5.6 || ^7.0"
+        "php": "^5.6 || ^7.0 || ^8.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.7.23 || ^6.4.3",
+        "phpunit/phpunit": "^5.7.23 || ^6.4.3 || ^7.0",
         "symfony/process": "^3.3"
     },
     "config": {

src/Output/UnifiedDiffOutputBuilder.php

@@ -67,11 +67,11 @@ public function getDiff(array $diff)
 
         \fclose($buffer);
 
-        // If the last char is not a linebreak: add it.
+        // If the diff is non-empty and a linebreak: add it.
         // This might happen when both the `from` and `to` do not have a trailing linebreak
         $last = \substr($diff, -1);
 
-        return "\n" !== $last && "\r" !== $last
+        return 0 !== \strlen($diff) && "\n" !== $last && "\r" !== $last
             ? $diff . "\n"
             : $diff
         ;

tests/Output/StrictUnifiedDiffOutputBuilderTest.php

@@ -305,6 +305,35 @@ public function testEmptyDiff()
         );
     }
 
+    /**
+     * @param string $from
+     * @param string $to
+     *
+     * @dataProvider provideSameEmptyDiff
+     */
+    public function testSameEmptyDiff($from, $to)
+    {
+        $builder = new StrictUnifiedDiffOutputBuilder([
+            'fromFile' => 'input.txt',
+            'toFile'   => 'output.txt',
+        ]);
+
+        $differ = new Differ($builder);
+
+        $this->assertSame(
+            '',
+            $differ->diff($from, $to)
+        );
+    }
+
+    public function provideSameEmptyDiff()
+    {
+        return [
+            ['', ''],
+            ['a', 'a'],
+        ];
+    }
+
     /**
      * @param array  $options
      * @param string $message

tests/Output/UnifiedDiffOutputBuilderTest.php

@@ -87,4 +87,28 @@ public function provideDiffWithLineNumbers()
     {
         return UnifiedDiffOutputBuilderDataProvider::provideDiffWithLineNumbers();
     }
+
+    /**
+     * @param string $from
+     * @param string $to
+     *
+     * @dataProvider provideStringsThatAreTheSame
+     */
+    public function testEmptyDiffProducesEmptyOutput($from, $to)
+    {
+        $differ = new Differ(new UnifiedDiffOutputBuilder('', false));
+        $output = $differ->diff($from, $to);
+        $this->assertEmpty($output);
+    }
+
+    public function provideStringsThatAreTheSame()
+    {
+        return [
+            ['', ''],
+            ['a', 'a'],
+            ['these strings are the same', 'these strings are the same'],
+            ["\n", "\n"],
+            ["multi-line strings\nare the same", "multi-line strings\nare the same"]
+        ];
+    }
 }