Zipdownload: add mbox_filter unit tests

Author: gurnec

plugins/zipdownload/tests/MboxFilterTest.php

@@ -0,0 +1,144 @@
+<?php
+
+namespace Roundcube\Plugins\Tests;
+
+use PHPUnit\Framework\TestCase;
+
+class MboxFilterTest extends TestCase
+{
+    private $fp;
+    private $filter;
+
+    #[\Override]
+    public static function setUpBeforeClass(): void
+    {
+        stream_filter_register('test_mbox_filter', '\Roundcube\Plugins\Tests\test_mbox_filter');
+    }
+
+    #[\Override]
+    protected function setUp(): void
+    {
+        $this->fp = fopen('php://memory', 'w+');
+        $this->filter = stream_filter_append($this->fp, 'test_mbox_filter', \STREAM_FILTER_WRITE);
+    }
+
+    /**
+     * Basic test with no special case
+     */
+    public function test_escape()
+    {
+        $this->assertIsResource($this->filter);
+        $this->assertSame(15, fwrite($this->fp, "test\nFrom \ntest"));
+        $this->assertTrue(stream_filter_remove($this->filter));
+        $this->assertTrue(rewind($this->fp));
+        $this->assertSame("test\n>From \ntest", fread($this->fp, 100));
+    }
+
+    /**
+     * The very first line may be escaped
+     */
+    public function test_escape_first_line()
+    {
+        fwrite($this->fp, '>From test');
+        $this->assertFalse(test_mbox_filter::was_maybe_split());
+        stream_filter_remove($this->filter);
+        rewind($this->fp);
+        $this->assertSame('>>From test', fread($this->fp, 100));
+    }
+
+    /**
+     * The beginning of a bucket which isn't the beginning of a new line
+     * must not be escaped
+     */
+    public function test_noescape_bucket_beginning()
+    {
+        fwrite($this->fp, 'test');
+        fwrite($this->fp, 'From ');
+        $this->assertFalse(test_mbox_filter::was_maybe_split());
+        stream_filter_remove($this->filter);
+        rewind($this->fp);
+        $this->assertSame('testFrom ', fread($this->fp, 100));
+    }
+
+    /**
+     * A split From line with a minimal portion in the first bucket
+     */
+    public function test_escape_split_min()
+    {
+        fwrite($this->fp, "test\n");
+        $this->assertTrue(test_mbox_filter::was_maybe_split());
+        fwrite($this->fp, 'From ');
+        $this->assertFalse(test_mbox_filter::was_maybe_split());
+        stream_filter_remove($this->filter);
+        rewind($this->fp);
+        $this->assertSame("test\n>From ", fread($this->fp, 100));
+    }
+
+    /**
+     * A split From line with a maximal portion in the first bucket
+     */
+    public function test_escape_split_max()
+    {
+        fwrite($this->fp, "test\n>From");
+        $this->assertTrue(test_mbox_filter::was_maybe_split());
+        fwrite($this->fp, ' ');
+        stream_filter_remove($this->filter);
+        rewind($this->fp);
+        $this->assertSame("test\n>>From ", fread($this->fp, 100));
+    }
+
+    /**
+     * A From line that is maybe-split in the first bucket, but not
+     * actually a split From line after seeing the second bucket
+     */
+    public function test_noescape_split()
+    {
+        fwrite($this->fp, "test\n>From");
+        $this->assertTrue(test_mbox_filter::was_maybe_split());
+        fwrite($this->fp, "\ntest");
+        stream_filter_remove($this->filter);
+        rewind($this->fp);
+        $this->assertSame("test\n>From\ntest", fread($this->fp, 100));
+    }
+
+    /**
+     * A From line that is maybe-split with no second bucket
+     */
+    public function test_noescape_split_last()
+    {
+        fwrite($this->fp, "test\n>From");
+        $this->assertTrue(test_mbox_filter::was_maybe_split());
+        stream_filter_remove($this->filter);
+        rewind($this->fp);
+        $this->assertSame("test\n>From", fread($this->fp, 100));
+    }
+}
+
+/**
+ * The assumption is that separate writes result in separate calls to
+ * zipdownload_mbox_filter::filter() which tries to detect a From line
+ * that might be split between calls. This checks the internal state of
+ * the most recently created (by PHP) zipdownload_mbox_filter to ensure
+ * that assumption is correct, otherwise the tests above may be invalid.
+ */
+class test_mbox_filter extends \zipdownload_mbox_filter
+{
+    private static $most_recently_created;
+
+    #[\Override]
+    public function onCreate(): bool
+    {
+        self::$most_recently_created = $this;
+        return parent::onCreate();
+    }
+
+    /**
+     * If prev_bucket is a bucket (a stdClass or StreamBucket object, depending
+     * on PHP version), zipdownload_mbox_filter's most recently seen bucket has
+     * what looks like a split From line at its end.
+     */
+    public static function was_maybe_split()
+    {
+        return is_object(self::$most_recently_created->prev_bucket);
+    }
+}

plugins/zipdownload/zipdownload.php

@@ -405,7 +405,7 @@ private function _filename_from_subject($str)
  */
 class zipdownload_mbox_filter extends \php_user_filter
 {
-    private $prev_bucket;
+    protected $prev_bucket;
     private $prev_match;
     private $first = true;