Test Processor invokes request, operation plugins

pyservice/processors.py

@@ -50,7 +50,7 @@ def __init__(self, obj, operation):
     def __call__(self):
         """ Entry point for external callers to begin processing """
         if self.scope is None:
-            raise ValueError("Already processed request")
+            raise RuntimeError("Already processed request")
         self.process_request()
         return self.result
 
@@ -90,18 +90,9 @@ def _continue(self):
         n = len(plugins)
         self.index += 1
 
-        # We're still working through the plugins for this scope
-        if self.index < n:
-            if self.scope == "request":
-                plugins[self.index]()
-            elif self.scope == "operation":
-                plugins[self.index](self.request, self.response, self.context)
-            else:
-                raise ValueError("Unexpected scope '{}'".format(self.scope))
-
         # We just processed the last plugin for this scope, either roll over
         # to the next scope or invoke the function underneath it all
-        elif self.index == n:
+        if self.index == n:
 
             # Determine the next scope and continue execution
             next_scope = self.transitions.get(self.scope, missing)
@@ -114,6 +105,22 @@ def _continue(self):
             else:
                 self._execute()
 
+        # We're still working through the plugins for this scope
+        else:  # self.index < n
+            # This is an assert instead of an exception because there's no
+            # single best way to recover from walking off the end of the
+            # available plugins - return, increment scope, raise?
+            assert self.index < n, "index exceeded length of plugins"
+
+            if self.scope == "request":
+                plugins[self.index](self.context)
+            elif self.scope == "operation":
+                plugins[self.index](self.request, self.response, self.context)
+            # Don't know how to handle plugins of other types, this is likely
+            # a bug.  Raise an error immediately instead of silently hanging
+            else:  # pragma: no cover
+                raise ValueError("Unexpected scope '{}'".format(self.scope))
+
     def _execute(self):  # pragma: no cover
         raise NotImplementedError("Subclasses must implement _execute.")
 

tests/test_processors.py

@@ -6,7 +6,10 @@
 class PluginObj:
     ''' Mock client/service with plugins '''
     def __init__(self):
-        self.plugins = {}
+        self.plugins = {
+            "request": [],
+            "operation": []
+        }
 
 
 class TestProcessor(processors.Processor):
@@ -15,6 +18,7 @@ def __init__(self, operation, result):
         obj = PluginObj()
         super().__init__(obj, operation)
         self.calls = collections.defaultdict(int)
+        self._plugin_obj = obj
         self._result = result
 
     def _execute(self):
@@ -53,5 +57,28 @@ def test_processor_multiple_calls():
     process = TestProcessor("not used", "also not used")
     process()
 
-    with pytest.raises(ValueError):
+    with pytest.raises(RuntimeError):
         process()
+
+
+def test_processor_plugin_scopes():
+    ''' Ensure plugins in request and operation scopes are invoked '''
+    operation = "my_operation"
+    process = TestProcessor(operation, "not used")
+
+    called = []
+
+    def request_plugin(context):
+        called.append("request")
+        assert context.operation == operation
+        context.process_request()
+    process._plugin_obj.plugins["request"].append(request_plugin)
+
+    def operation_plugin(request, response, context):
+        called.append("operation")
+        assert context.operation == operation
+        context.process_request()
+    process._plugin_obj.plugins["operation"].append(operation_plugin)
+
+    process()
+    assert called == ["request", "operation"]