diff --git a/dist/tests/01-ping-pong.js b/dist/tests/01-ping-pong.js
index dda4210..9f256d1 100644
--- a/dist/tests/01-ping-pong.js
+++ b/dist/tests/01-ping-pong.js
@@ -15,6 +15,9 @@
   var Goto = function(targetStateName) {
     return { type: "Goto", targetStateName };
   };
+  var Context = function(fn) {
+    return { type: "ContextMutation", fn };
+  };
   function interpret(machine, options) {
     let { state, context } = options;
     if (typeof state === "undefined") {
@@ -86,11 +89,11 @@
     send(ctx.clientActor, ["received-response", self]);
   };
   var startTimer = async (ctx, e, self) => {
-    await wait(500);
+    await wait(1500);
     send(self, ["timer-finished", null]);
   };
   var log = (ctx, e, self) => {
-    console.log(self.state);
+    console.log(self.state, ctx);
   };
   var client = Machine(
     State(
@@ -113,6 +116,7 @@
         "entry",
         SideEffect(log),
         SideEffect(makeRequest),
+        Context((ctx) => ({ ...ctx, requestsMade: ctx.requestsMade + 1 })),
         Goto("awaiting-response")
       )
     ),
@@ -125,6 +129,7 @@
       On(
         "received-response",
         SideEffect(log),
+        Context((ctx) => ({ ...ctx, responsesReceived: ctx.responsesReceived + 1 })),
         Goto("making-request")
       )
     )
@@ -158,7 +163,7 @@
       )
     )
   );
-  var clientActor = interpret(client, { context: {} });
+  var clientActor = interpret(client, { context: { requestsMade: 0, responsesReceived: 0 } });
   var serverActor = interpret(server, { context: {} });
   send(clientActor, ["server-created", serverActor]);
 })();
diff --git a/src/tests/01-ping-pong.ts b/src/tests/01-ping-pong.ts
index 2c7b5a1..330b0f0 100644
--- a/src/tests/01-ping-pong.ts
+++ b/src/tests/01-ping-pong.ts
@@ -1,21 +1,10 @@
-import { Machine, State, On, SideEffect, Goto, Spawn, Unspawn, interpret, Interpreter_T, send, Event_T } from '../index';
+import { Machine, State, On, SideEffect, Goto, Spawn, Unspawn, interpret, Interpreter_T, send, Event_T, Context } from '../index';
 
 const wait = (ms:number)=>new Promise((resolve)=>{ setTimeout(()=>{ resolve(1); }, ms); });
 const makeRequest = (ctx,e,self)=>{ send(ctx.serverActor, ['received-request',self]); };
 const sendResponse = (ctx,e,self)=>{ send(ctx.clientActor, ['received-response',self]); };
-const startTimer = async (ctx,e,self)=>{ await wait(500); send(self, ['timer-finished',null]); }
-const log = (ctx, e, self:Interpreter_T)=>{ console.log(self.state); };
-
-type Sc = 
-  | 'idle' 
-  | 'making-request' 
-  | 'awaiting-response';
-type Ec = 
-  | ['entry',null] 
-  | ['received-response',Interpreter_T]
-  | ['server-created', Interpreter_T];
-type Cc = 
-  | {serverActor?:Interpreter_T};
+const startTimer = async (ctx,e,self)=>{ await wait(1500); send(self, ['timer-finished',null]); }
+const log = (ctx, e, self:Interpreter_T)=>{ console.log(self.state, ctx); };
 
 const client = 
   Machine(
@@ -32,6 +21,7 @@ const client =
       On('entry', 
         SideEffect(log),
         SideEffect(makeRequest),
+        Context((ctx)=>({...ctx, requestsMade: ctx.requestsMade+1})),
         Goto('awaiting-response')
       ),
     ),
@@ -41,20 +31,12 @@ const client =
       ),
       On('received-response', 
         SideEffect(log),
+        Context((ctx)=>({...ctx, responsesReceived: ctx.responsesReceived+1})),
         Goto('making-request')
       ),
     ),
   );
 
-type Ss = 
-  | 'awaiting-request' 
-  | 'sending-response';
-type Es = 
-  | ['entry',null] 
-  | ['received-request',Interpreter_T]
-  | ['timer-finished', null];
-type Cs = {clientActor?:Interpreter_T};
-
 const server = 
   Machine(
     State('awaiting-request',
@@ -78,6 +60,6 @@ const server =
     ),
   );
 
-const clientActor = interpret(client, {context:{}});
+const clientActor = interpret(client, {context:{requestsMade:0, responsesReceived:0}});
 const serverActor = interpret(server, {context:{}});
 send(clientActor, ['server-created', serverActor]);
\ No newline at end of file