From e1af6f13ace6863e5bf2de22f8b70c2c04d82961 Mon Sep 17 00:00:00 2001
From: BlackMATov <blackmatov@gmail.com>
Date: Sun, 9 Dec 2018 22:45:05 +0700
Subject: [PATCH] make_promise function also can create pending promises

---
 promise.hpp |  5 +++++
 tests.cpp   | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/promise.hpp b/promise.hpp
index 3eb8a4c..43186b4 100644
--- a/promise.hpp
+++ b/promise.hpp
@@ -656,6 +656,11 @@ namespace promise_hpp
     // make_promise
     //
 
+    template < typename R >
+    promise<R> make_promise() {
+        return promise<R>();
+    }
+
     template < typename R, typename F >
     promise<R> make_promise(F&& f) {
         promise<R> result;
diff --git a/tests.cpp b/tests.cpp
index 8ce75c1..5c642e1 100644
--- a/tests.cpp
+++ b/tests.cpp
@@ -426,6 +426,25 @@ TEST_CASE("promise") {
             REQUIRE(check_84_int == 84);
         }
     }
+    SECTION("lazy_chaining") {
+        {
+            int check_84_int = 0;
+            auto p1 = pr::make_promise<int>();
+            auto p2 = pr::make_promise<int>();
+
+            p1.then([&p2](int v){
+                return p2;
+            }).then([&check_84_int](int v2){
+                check_84_int = v2;
+            });
+
+            REQUIRE(check_84_int == 0);
+            p1.resolve(42);
+            REQUIRE(check_84_int == 0);
+            p2.resolve(84);
+            REQUIRE(check_84_int == 84);
+        }
+    }
     SECTION("typed_chaining_fails") {
         {
             bool call_fail_with_logic_error = false;