Add support for pre resolved/rejected promises

Signed-off-by: Greg Haskins <[email protected]>

Author: ghaskins

src/temporal/promise.clj

@@ -5,7 +5,7 @@
   (:require [promesa.core :as p]
             [temporal.internal.promise :as pt])
   (:import [temporal.internal.promise PromiseAdapter]
-           [io.temporal.workflow Promise]))
+           [io.temporal.workflow Workflow Promise]))
 
 (defn- ->array
   ^"[Lio.temporal.workflow.Promise;" [coll]
@@ -44,4 +44,14 @@ promises returned from [[temporal.activity/invoke]] from within workflow context
 ```
 "
   [coll]
-  (pt/->PromiseAdapter (Promise/anyOf (->array coll))))
+  (pt/->PromiseAdapter (Promise/anyOf (->array coll))))
+
+(defn resolved
+  "Returns a new, fully resolved promise"
+  [value]
+  (Workflow/newPromise value))
+
+(defn rejected
+  "Returns a new, rejected promise"
+  [^Exception e]
+  (Workflow/newFailedPromise e))

test/temporal/test/sequence.clj

@@ -0,0 +1,33 @@
+;; Copyright © 2022 Manetu, Inc.  All rights reserved
+
+(ns temporal.test.sequence
+  (:require [clojure.test :refer :all]
+            [promesa.core :as p]
+            [taoensso.timbre :as log]
+            [temporal.client.core :as c]
+            [temporal.workflow :refer [defworkflow]]
+            [temporal.activity :refer [defactivity] :as a]
+            [temporal.test.utils :as t]
+            [temporal.promise :as pt]))
+
+(use-fixtures :once t/wrap-service)
+
+(defactivity greet-activity
+  [ctx args]
+  (log/info "greet-activity:" args)
+  (str "Hi, " args))
+
+(defworkflow sequence-workflow
+  [ctx _]
+  @(-> (pt/resolved true)
+       (p/then (fn [_]
+                 (a/invoke greet-activity "Bob")))
+       (p/then (fn [_]
+                 (a/invoke greet-activity "Charlie")))
+       (p/then (constantly :ok))))
+
+(deftest the-test
+  (testing "Verifies that we can process a promise-chain in sequence"
+    (let [workflow (t/create-workflow sequence-workflow)]
+      (c/start workflow nil)
+      (is (= @(c/get-result workflow) :ok)))))