Add functionality to create CSV response from array and traversable

In addition to the refactor to create the CSV response from a string,
this change adds the ability to create the CSV response from a plain old
PHP array as well as a Traversable. I'm not altogether happy with the
naming of some of the functions and variables, but will address that,
just as soon as I can think of better names.

src/Response/CsvResponse.php

@@ -10,6 +10,7 @@
 namespace Zend\Diactoros\Response;
 
 use Psr\Http\Message\StreamInterface;
+use Traversable;
 use Zend\Diactoros\Exception;
 use Zend\Diactoros\Response;
 use Zend\Diactoros\Stream;
@@ -31,6 +32,7 @@ class CsvResponse extends DownloadResponse
 {
     use InjectContentTypeTrait;
 
+    const DEFAULT_LINE_ENDING = "\n";
     const DEFAULT_SEPARATOR = ',';
 
     /**
@@ -83,6 +85,10 @@ private function createBody($text) : StreamInterface
             $body = $text;
         }
 
+        if (is_array($text) | $text instanceof Traversable) {
+            $body = $this->createBodyFromIterable($text);
+        }
+
         return $body;
     }
 
@@ -109,6 +115,25 @@ private function createBodyFromString(string $text) : StreamInterface
         return $body;
     }
 
+    /**
+     * Create the CSV response body from the contents of an array
+     * @param array|Traversable $text
+     * @return StreamInterface
+     */
+    public function createBodyFromIterable($text) : StreamInterface
+    {
+        $body = new Stream('php://temp', 'wb+');
+        $last = end($text);
+        reset($text);
+
+        foreach ($text as $row) {
+            $body->write($this->getRecord($row, $last));
+        }
+        $body->rewind();
+
+        return $body;
+    }
+
     /**
      * Get a fully rendered CSV record
      * @param array $row

test/Response/CsvResponseTest.php

@@ -28,6 +28,101 @@ public function testConstructorAcceptsBodyAsString()
         $this->assertSame(200, $response->getStatusCode());
     }
 
+    /**
+     * @dataProvider arrayToBodyDataProvider
+     * @param array $input
+     * @param string $output
+     * @param array $options
+     */
+    public function testConstructorAcceptsArrayAsBody($input, string $output, array $options)
+    {
+        $response = new CsvResponse($input, $options);
+        $this->assertSame($output, (string) $response->getBody());
+        $this->assertSame(200, $response->getStatusCode());
+    }
+
+    public function arrayToBodyDataProvider()
+    {
+        $bodyWithCommaAsFieldSeparatorOutput = <<<EOF
+first,last,email,dob
+john,citizen,john.citizen@afakeemailaddress.com,01/01/1970
+EOF;
+
+        $bodyWithTabAsFieldSeparatorOutput = <<<EOF
+first	last	email	dob
+john	citizen	john.citizen@afakeemailaddress.com	01/01/1970
+EOF;
+
+        $bodyWithSemicolonAsFieldSeparatorOutput = <<<EOF
+first;last;email;dob
+john;citizen;john.citizen@afakeemailaddress.com;01/01/1970
+EOF;
+
+        $bodyWithSemicolonAsFieldSeparatorAndCarriageReturnNewlineAsLineEndingOutput = <<<EOF
+first;last;email;dob\r
+john;citizen;john.citizen@afakeemailaddress.com;01/01/1970
+EOF;
+
+        $iterator = new \ArrayIterator(
+            [
+                ["first","last","email","dob"],
+                ["john","citizen","john.citizen@afakeemailaddress.com","01/01/1970"],
+            ]
+        );
+
+        return [
+            [
+                [
+                    ["first","last","email","dob"],
+                    ["john","citizen","john.citizen@afakeemailaddress.com","01/01/1970"],
+                ],
+                $bodyWithCommaAsFieldSeparatorOutput,
+                [
+                    "field_separator" => ',',
+                ],
+            ],
+            [
+                [
+                    ["first","last","email","dob"],
+                    ["john","citizen","john.citizen@afakeemailaddress.com","01/01/1970"],
+                ],
+                $bodyWithTabAsFieldSeparatorOutput,
+                [
+                    "field_separator" => "\t",
+                ],
+            ],
+            [
+                [
+                    ["first","last","email","dob"],
+                    ["john","citizen","john.citizen@afakeemailaddress.com","01/01/1970"],
+                ],
+                $bodyWithSemicolonAsFieldSeparatorOutput,
+                [
+                    "field_separator" => ";",
+                ],
+            ],
+            [
+                [
+                    ["first","last","email","dob"],
+                    ["john","citizen","john.citizen@afakeemailaddress.com","01/01/1970"],
+                ],
+                $bodyWithSemicolonAsFieldSeparatorAndCarriageReturnNewlineAsLineEndingOutput,
+                [
+                    "field_separator" => ";",
+                    "line_ending" => "\r\n",
+                ],
+            ],
+            [
+                $iterator,
+                $bodyWithSemicolonAsFieldSeparatorAndCarriageReturnNewlineAsLineEndingOutput,
+                [
+                    "field_separator" => ";",
+                    "line_ending" => "\r\n",
+                ],
+            ],
+        ];
+    }
+
     public function testConstructorAllowsPassingStatus()
     {
         $status = 404;