Adds method based options, limited to one, to allow nodes based on a specific method (think filter, join, etc)...

Reimplementation of "Filter", with (rather simple) code from rdc.etl.

tests/test_config_method.py

@@ -0,0 +1,73 @@
+import pytest
+
+from bonobo.config import Configurable, Method, Option
+from bonobo.errors import ConfigurationError
+
+
+class MethodBasedConfigurable(Configurable):
+    handler = Method()
+    foo = Option(positional=True)
+    bar = Option()
+
+    def call(self, *args, **kwargs):
+        self.handler(*args, **kwargs)
+
+
+def test_one_wrapper_only():
+    with pytest.raises(ConfigurationError):
+        class TwoMethods(Configurable):
+            h1 = Method()
+            h2 = Method()
+
+
+def test_define_with_decorator():
+    calls = []
+
+    @MethodBasedConfigurable
+    def Concrete(self, *args, **kwargs):
+        calls.append((args, kwargs,))
+
+    t = Concrete('foo', bar='baz')
+    assert len(calls) == 0
+    t()
+    assert len(calls) == 1
+
+
+def test_define_with_argument():
+    calls = []
+
+    def concrete_handler(*args, **kwargs):
+        calls.append((args, kwargs,))
+
+    t = MethodBasedConfigurable('foo', bar='baz', handler=concrete_handler)
+    assert len(calls) == 0
+    t()
+    assert len(calls) == 1
+
+def test_define_with_inheritance():
+    calls = []
+
+    class Inheriting(MethodBasedConfigurable):
+        def handler(self, *args, **kwargs):
+            calls.append((args, kwargs,))
+
+    t = Inheriting('foo', bar='baz')
+    assert len(calls) == 0
+    t()
+    assert len(calls) == 1
+
+
+def test_inheritance_then_decorate():
+    calls = []
+
+    class Inheriting(MethodBasedConfigurable):
+        pass
+
+    @Inheriting
+    def Concrete(self, *args, **kwargs):
+        calls.append((args, kwargs,))
+
+    t = Concrete('foo', bar='baz')
+    assert len(calls) == 0
+    t()
+    assert len(calls) == 1

tests/test_execution.py

@@ -59,11 +59,24 @@ def test_simple_execution_context():
         assert ctx[i].wrapped is node
 
     assert not ctx.alive
+    assert not ctx.started
+    assert not ctx.stopped
 
     ctx.recv(BEGIN, Bag(), END)
 
     assert not ctx.alive
+    assert not ctx.started
+    assert not ctx.stopped
 
     ctx.start()
 
     assert ctx.alive
+    assert ctx.started
+    assert not ctx.stopped
+
+    ctx.stop()
+
+    assert not ctx.alive
+    assert ctx.started
+    assert ctx.stopped
+