Includes regression test for tasks

test/source/browser/browser-tests.js

@@ -16,6 +16,7 @@ process.env.FOLKTALE_ASSERTIONS = 'none';
 require('../specs/base/adt/union');
 require('../specs/base/concurrency/future');
 require('../specs/base/concurrency/task');
+require('../specs/base/concurrency/regression/task-cancellation-174');
 require('../specs/base/core/lambda');
 require('../specs/base/core/object');
 require('../specs/base/fantasy-land/fantasy-land');

test/source/specs/base/concurrency/regression/task-cancellation-174.js

@@ -0,0 +1,59 @@
+//----------------------------------------------------------------------
+//
+// This source file is part of the Folktale project.
+//
+// Licensed under MIT. See LICENCE for full licence information.
+// See CONTRIBUTORS for the list of contributors to the project.
+//
+//----------------------------------------------------------------------
+
+// See https://github.com/origamitower/folktale/issues/174 for details
+
+const { task } = require('folktale/concurrency/task');
+
+it('concurrency Regression: chained tasks are not cancelled if partially settled', (done) => {
+  const started = [];
+  const finished = [];
+  let isCancelled = false;
+
+  const delay = (ms, data) => task(resolver => {
+    started.push(data);
+    const timer = setTimeout(() => {
+      finished.push(data);
+      if (isCancelled)  return;
+      resolver.resolve(data)
+    }, ms);
+    resolver.onCancelled(() => clearTimeout(timer));
+  });
+
+  const chain = delay(100, 'a')
+    .chain(x => delay(100, 'b'))
+    .chain(x => delay(100, 'c'));
+
+  const execution = chain.run();
+  setTimeout(() => {
+    isCancelled = true;
+    execution.cancel()
+  }, 150);
+
+  execution.listen({
+    onCancelled: () => {
+      if (started.join(',') === 'a,b' && finished.join(',') === 'a') {
+        done(null);
+      } else {
+        done(new Error(`Task was cancelled, but expected a and b to be started, but only a to be finished. 
+Got ${started.join(', ')} started and ${finished.join(', ')} finished`));
+      }
+    },
+
+    onResolved: () => {
+      done(new Error(`Expected task chain to be cancelled, but they were resolved.`));
+    },
+
+    onRejected: () => {
+      done(new Error(`Expected task chain to be cancelled, but they were rejected.`));
+    }
+  })
+
+
+});