Test case regarding randomization of shuffle() and str_shuffle().

The code was provided by Adam Trachtenberg : adam trachtenberg com

diff --git a/ext/standard/tests/strings/004.phpt b/ext/standard/tests/strings/004.phpt
new file mode 100644 (file)
index 0000000..de721ef
--- /dev/null
+++ b/ext/standard/tests/strings/004.phpt
@@ -0,0 +1,84 @@
+--TEST--
+Testing randomization of shuffle() and str_shuffle().
+--FILE--
+<?php
+function stats($f, $a) {
+    $times = 90000;
+    print "$f\n";
+    ksort($a);
+    foreach($a as $k => $v)
+        print "$k: $v: " . sprintf('%0.3f', $v / $times) . "\n";
+}
+$a = array();
+$times = 90000;
+for ($i = 0; $i < $times; $i++) {
+    $p = range(1,4);
+    shuffle($p);
+    $s = join('', $p);
+    if (empty($a[$s])) $a[$s] = 0; 
+    $a[$s]++;
+}
+
+stats('shuffle', $a);
+$a = array();
+$times = 90000;
+for ($i = 0; $i < $times; $i++) {
+    $p = '1234';
+    $s = str_shuffle($p);
+    if (empty($a[$s])) $a[$s] = 0;
+    $a[$s]++;
+}
+
+stats('str_shuffle', $a);
+?>
+--EXPECTF--
+shuffle
+1234: 3%d: 0.04%d
+1243: 3%d: 0.04%d
+1324: 3%d: 0.04%d
+1342: 3%d: 0.04%d
+1423: 3%d: 0.04%d
+1432: 3%d: 0.04%d
+2134: 3%d: 0.04%d
+2143: 3%d: 0.04%d
+2314: 3%d: 0.04%d
+2341: 3%d: 0.04%d
+2413: 3%d: 0.04%d
+2431: 3%d: 0.04%d
+3124: 3%d: 0.04%d
+3142: 3%d: 0.04%d
+3214: 3%d: 0.04%d
+3241: 3%d: 0.04%d
+3412: 3%d: 0.04%d
+3421: 3%d: 0.04%d
+4123: 3%d: 0.04%d
+4132: 3%d: 0.04%d
+4213: 3%d: 0.04%d
+4231: 3%d: 0.04%d
+4312: 3%d: 0.04%d
+4321: 3%d: 0.04%d
+str_shuffle
+1234: 3%d: 0.04%d
+1243: 3%d: 0.04%d
+1324: 3%d: 0.04%d
+1342: 3%d: 0.04%d
+1423: 3%d: 0.04%d
+1432: 3%d: 0.04%d
+2134: 3%d: 0.04%d
+2143: 3%d: 0.04%d
+2314: 3%d: 0.04%d
+2341: 3%d: 0.04%d
+2413: 3%d: 0.04%d
+2431: 3%d: 0.04%d
+3124: 3%d: 0.04%d
+3142: 3%d: 0.04%d
+3214: 3%d: 0.04%d
+3241: 3%d: 0.04%d
+3412: 3%d: 0.04%d
+3421: 3%d: 0.04%d
+4123: 3%d: 0.04%d
+4132: 3%d: 0.04%d
+4213: 3%d: 0.04%d
+4231: 3%d: 0.04%d
+4312: 3%d: 0.04%d
+4321: 3%d: 0.04%d