Fix empty array parsing

Closes #21.

Author: trowski

src/Internal/ArrayParser.php

@@ -42,15 +42,23 @@ public function parse(string $data, callable $cast = null, string $delimiter = '
      */
     private function parser(string $data, callable $cast = null, string $delimiter = ','): \Generator
     {
-        if ($data[0] !== '{' || \substr($data, -1) !== '}') {
-            throw new ParseException("Missing opening or closing brackets");
+        if ($data === '') {
+            throw new ParseException("Unexpected end of data");
+        }
+
+        if ($data[0] !== '{') {
+            throw new ParseException("Missing opening bracket");
         }
 
         $data = \ltrim(\substr($data, 1));
 
         do {
             if ($data === '') {
-                throw new ParseException("Missing closing bracket");
+                throw new ParseException("Unexpected end of data");
+            }
+
+            if ($data[0] === '}') { // Empty array
+                return \ltrim(\substr($data, 1));
             }
 
             if ($data[0] === '{') { // Array

test/ArrayParserTest.php

@@ -128,15 +128,79 @@ public function testEscapedBackslashesInQuotedValue()
         $this->assertSame($array, $this->parser->parse($string));
     }
 
+    public function testEmptyArray()
+    {
+        $array = [];
+        $string = '{}';
+
+        $this->assertSame($array, $this->parser->parse($string));
+    }
+
+    public function testArrayContainingEmptyArray()
+    {
+        $array = [[], [1], []];
+        $string = '{{},{1},{}}';
+
+        $cast = function (string $value): int {
+            return (int) $value;
+        };
+
+        $this->assertSame($array, $this->parser->parse($string, $cast));
+    }
+
+    public function testArrayWithEmptyString()
+    {
+        $array = [''];
+        $string = '{""}';
+
+        $this->assertSame($array, $this->parser->parse($string));
+    }
+
+    public function testMalformedNestedArray()
+    {
+        $this->expectException(ParseException::class);
+        $this->expectExceptionMessage('Unexpected end of data');
+
+        $string = '{{}';
+        $this->parser->parse($string);
+    }
+
+    public function testEmptyString()
+    {
+        $this->expectException(ParseException::class);
+        $this->expectExceptionMessage('Unexpected end of data');
+
+        $string = ' ';
+        $this->parser->parse($string);
+    }
+
+    public function testNoOpeningBracket()
+    {
+        $this->expectException(ParseException::class);
+        $this->expectExceptionMessage('Missing opening bracket');
+
+        $string = '"one", "two"}';
+        $this->parser->parse($string);
+    }
+
     public function testNoClosingBracket()
     {
         $this->expectException(ParseException::class);
-        $this->expectExceptionMessage('Missing opening or closing brackets');
+        $this->expectExceptionMessage('Unexpected end of data');
 
         $string = '{"one", "two"';
         $this->parser->parse($string);
     }
 
+    public function testExtraClosingBracket()
+    {
+        $this->expectException(ParseException::class);
+        $this->expectExceptionMessage('Data left in buffer after parsing');
+
+        $string = '{"one", "two"}}';
+        $this->parser->parse($string);
+    }
+
     public function testTrailingData()
     {
         $this->expectException(ParseException::class);