diff --git a/bonobo/core/contexts.py b/bonobo/core/contexts.py
index d0ed27d..0c0820a 100644
--- a/bonobo/core/contexts.py
+++ b/bonobo/core/contexts.py
@@ -71,7 +71,7 @@ class PluginExecutionContext:
         self.alive = False
 
 
-def iterable(x):
+def _iter(x):
     if isinstance(x, (dict, list, str)):
         raise TypeError(type(x).__name__)
     return iter(x)
@@ -173,7 +173,7 @@ class ComponentExecutionContext(WithStatistics):
         # self._exec_time += timer.duration
         # Put data onto output channels
         try:
-            results = iterable(results)
+            results = _iter(results)
         except TypeError:
             if results:
                 self.send(_resolve(results))
diff --git a/tests/core/test_contexts.py b/tests/core/test_contexts.py
index e69de29..e2e6179 100644
--- a/tests/core/test_contexts.py
+++ b/tests/core/test_contexts.py
@@ -0,0 +1,34 @@
+from bonobo import Graph
+from bonobo.core.contexts import ExecutionContext
+
+
+def generate_integers():
+    yield from range(10)
+
+
+def square(i: int) -> int:
+    return i**2
+
+
+def test_empty_execution_context():
+    graph = Graph()
+
+    ctx = ExecutionContext(graph)
+    assert not len(ctx.components)
+    assert not len(ctx.plugins)
+
+    assert not ctx.running
+
+
+def test_simple_execution_context():
+    graph = Graph()
+    graph.add_chain(generate_integers, square)
+
+    ctx = ExecutionContext(graph)
+    assert len(ctx.components) == 2
+    assert not len(ctx.plugins)
+
+    assert ctx[0].component is generate_integers
+    assert ctx[1].component is square
+
+    assert not ctx.running