Add missing test files

tests/Queue/iteration.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Queue: Test iteration
+--FILE--
+<?php
+
+$queue = new SPL\Datastructures\Queue;
+var_dump($queue instanceof Traversable);
+
+$queue->push('x');
+$queue->push('y');
+$queue->push('z');
+
+foreach ($queue as $index => $item) {
+    var_dump($index, $item);
+}
+
+?>
+--EXPECT--
+bool(true)
+int(0)
+string(1) "x"
+int(1)
+string(1) "y"
+int(2)
+string(1) "z"

tests/Queue/popPeekError.phpt

@@ -0,0 +1,23 @@
+--TEST--
+Queue: UnderflowException on $queue->peek() and $queue->pop() for empty queue
+--FILE--
+<?php
+
+$queue = new SPL\Datastructures\Queue;
+
+try {
+    $queue->peek();
+} catch (UnderflowException $e) {
+    var_dump($e->getMessage());
+}
+
+try {
+    $queue->pop();
+} catch (UnderflowException $e) {
+    var_dump($e->getMessage());
+}
+
+?>
+--EXPECT--
+string(25) "Can't peek an empty queue"
+string(24) "Can't pop an empty queue"

tests/Stack/iteration.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Stack: Test iteration
+--FILE--
+<?php
+
+$stack = new SPL\Datastructures\Stack;
+var_dump($stack instanceof Traversable);
+
+$stack->push('x');
+$stack->push('y');
+$stack->push('z');
+
+foreach ($stack as $index => $item) {
+    var_dump($index, $item);
+}
+
+?>
+--EXPECT--
+bool(true)
+int(0)
+string(1) "x"
+int(1)
+string(1) "y"
+int(2)
+string(1) "z"

tests/Stack/popPeekError.phpt

@@ -0,0 +1,23 @@
+--TEST--
+Stack: UnderflowException on $stack->peek() and $stack->pop() for empty stack
+--FILE--
+<?php
+
+$stack = new SPL\Datastructures\Stack;
+
+try {
+    $stack->peek();
+} catch (UnderflowException $e) {
+    var_dump($e->getMessage());
+}
+
+try {
+    $stack->pop();
+} catch (UnderflowException $e) {
+    var_dump($e->getMessage());
+}
+
+?>
+--EXPECT--
+string(25) "Can't peek an empty stack"
+string(24) "Can't pop an empty stack"