Add awaitCompletion tests for nested spawn and child scopes

Cover scenarios not previously tested:
- spawn() inside scope's coroutine (same scope inheritance)
- child scope via Scope::inherit() with active coroutines
- grandchild scope cascading completion
- deeply nested spawn() chains

Author: EdmondDantes

tests/scope/037-scope_awaitCompletion_nested_spawn.phpt

@@ -0,0 +1,55 @@
+--TEST--
+Scope: awaitCompletion() waits for coroutines spawned inside scope's coroutines
+--FILE--
+<?php
+
+use Async\Scope;
+use function Async\spawn;
+use function Async\await;
+use function Async\delay;
+use function Async\timeout;
+
+echo "start\n";
+
+$scope = Scope::inherit();
+$results = [];
+
+$scope->spawn(function() use (&$results) {
+    $results[] = 'parent_start';
+
+    // Nested spawn() — should go into the same scope via ZEND_ASYNC_CURRENT_SCOPE
+    spawn(function() use (&$results) {
+        delay(50);
+        $results[] = 'child_1';
+    });
+
+    spawn(function() use (&$results) {
+        delay(100);
+        $results[] = 'child_2';
+    });
+
+    $results[] = 'parent_end';
+});
+
+$external = spawn(function() use ($scope) {
+    try {
+        $scope->awaitCompletion(timeout(2000));
+        echo "scope completed\n";
+    } catch (\Async\OperationCanceledException $e) {
+        echo "ERROR: timed out\n";
+    }
+});
+
+await($external);
+
+echo "results: " . implode(', ', $results) . "\n";
+echo "finished: " . ($scope->isFinished() ? "true" : "false") . "\n";
+echo "end\n";
+
+?>
+--EXPECT--
+start
+scope completed
+results: parent_start, parent_end, child_1, child_2
+finished: true
+end

tests/scope/038-scope_awaitCompletion_child_scope.phpt

@@ -0,0 +1,60 @@
+--TEST--
+Scope: awaitCompletion() waits for child scopes created via Scope::inherit()
+--FILE--
+<?php
+
+use Async\Scope;
+use function Async\spawn;
+use function Async\await;
+use function Async\delay;
+use function Async\timeout;
+
+echo "start\n";
+
+$scope = Scope::inherit();
+$results = [];
+$childScopeRef = null;
+
+$scope->spawn(function() use (&$results, &$childScopeRef) {
+    $results[] = 'parent_start';
+
+    // Create child scope — inherits from ZEND_ASYNC_CURRENT_SCOPE = $scope
+    $childScopeRef = Scope::inherit();
+
+    $childScopeRef->spawn(function() use (&$results) {
+        delay(50);
+        $results[] = 'child_scope_coroutine_1';
+    });
+
+    $childScopeRef->spawn(function() use (&$results) {
+        delay(100);
+        $results[] = 'child_scope_coroutine_2';
+    });
+
+    $results[] = 'parent_end';
+});
+
+$external = spawn(function() use ($scope) {
+    try {
+        $scope->awaitCompletion(timeout(2000));
+        echo "scope completed\n";
+    } catch (\Async\OperationCanceledException $e) {
+        echo "ERROR: timed out\n";
+    }
+});
+
+await($external);
+
+echo "results: " . implode(', ', $results) . "\n";
+echo "parent finished: " . ($scope->isFinished() ? "true" : "false") . "\n";
+echo "child finished: " . ($childScopeRef->isFinished() ? "true" : "false") . "\n";
+echo "end\n";
+
+?>
+--EXPECT--
+start
+scope completed
+results: parent_start, parent_end, child_scope_coroutine_1, child_scope_coroutine_2
+parent finished: true
+child finished: true
+end

tests/scope/039-scope_awaitCompletion_grandchild.phpt

@@ -0,0 +1,55 @@
+--TEST--
+Scope: awaitCompletion() waits for grandchild scopes (cascading completion)
+--FILE--
+<?php
+
+use Async\Scope;
+use function Async\spawn;
+use function Async\await;
+use function Async\delay;
+use function Async\timeout;
+
+echo "start\n";
+
+$scope = Scope::inherit();
+$results = [];
+$childRef = null;
+$grandchildRef = null;
+
+$scope->spawn(function() use (&$results, &$childRef, &$grandchildRef) {
+    $results[] = 'level_0';
+
+    $childRef = Scope::inherit();
+    $childRef->spawn(function() use (&$results, &$grandchildRef) {
+        $results[] = 'level_1';
+
+        $grandchildRef = Scope::inherit();
+        $grandchildRef->spawn(function() use (&$results) {
+            delay(50);
+            $results[] = 'level_2';
+        });
+    });
+});
+
+$external = spawn(function() use ($scope) {
+    try {
+        $scope->awaitCompletion(timeout(2000));
+        echo "scope completed\n";
+    } catch (\Async\OperationCanceledException $e) {
+        echo "ERROR: timed out\n";
+    }
+});
+
+await($external);
+
+echo "results: " . implode(', ', $results) . "\n";
+echo "finished: " . ($scope->isFinished() ? "true" : "false") . "\n";
+echo "end\n";
+
+?>
+--EXPECT--
+start
+scope completed
+results: level_0, level_1, level_2
+finished: true
+end

tests/scope/040-scope_awaitCompletion_nested_spawn_deep.phpt

@@ -0,0 +1,58 @@
+--TEST--
+Scope: awaitCompletion() waits for deeply nested spawn() chains
+--FILE--
+<?php
+
+use Async\Scope;
+use function Async\spawn;
+use function Async\await;
+use function Async\delay;
+use function Async\timeout;
+
+echo "start\n";
+
+$scope = Scope::inherit();
+$results = [];
+
+// Coroutine spawns coroutine spawns coroutine — all in the same scope
+$scope->spawn(function() use (&$results) {
+    $results[] = 'a';
+
+    spawn(function() use (&$results) {
+        $results[] = 'b';
+        delay(20);
+
+        spawn(function() use (&$results) {
+            $results[] = 'c';
+            delay(20);
+
+            spawn(function() use (&$results) {
+                delay(20);
+                $results[] = 'd';
+            });
+        });
+    });
+});
+
+$external = spawn(function() use ($scope) {
+    try {
+        $scope->awaitCompletion(timeout(2000));
+        echo "scope completed\n";
+    } catch (\Async\OperationCanceledException $e) {
+        echo "ERROR: timed out\n";
+    }
+});
+
+await($external);
+
+echo "results: " . implode(', ', $results) . "\n";
+echo "finished: " . ($scope->isFinished() ? "true" : "false") . "\n";
+echo "end\n";
+
+?>
+--EXPECT--
+start
+scope completed
+results: a, b, c, d
+finished: true
+end