protocols: make playbooks immutable

mitmproxy/proxy/protocol2/test/test_tutils.py

@@ -0,0 +1,59 @@
+import typing
+
+from mitmproxy.proxy.protocol2 import events, commands
+from mitmproxy.proxy.protocol2.layer import Layer
+from mitmproxy.proxy.protocol2.test import tutils
+from mitmproxy.proxy.protocol2.utils import expect
+
+
+class TEvent(events.Event):
+    commands: typing.Iterable[typing.Any]
+
+    def __init__(self, cmds=(None,)):
+        self.commands = cmds
+
+
+class TCommand(commands.Command):
+    x: typing.Any
+
+    def __init__(self, x=None):
+        self.x = x
+
+
+class TLayer(Layer):
+    """
+    Simple echo layer
+    """
+
+    @expect(TEvent)
+    def _handle_event(self, event: TEvent) -> commands.TCommandGenerator:
+        for x in event.commands:
+            yield TCommand(x)
+
+
+def test_playbook_simple(tctx):
+    playbook = tutils.playbook(TLayer(tctx), [])
+    assert (
+        playbook
+        >> TEvent()
+        << TCommand()
+        >> TEvent([])
+        << None
+    )
+
+
+def test_playbook_partial_assert(tctx):
+    playbook = tutils.playbook(TLayer(tctx), [])
+    playbook = (
+        playbook
+        >> TEvent()
+        << TCommand()
+    )
+    assert playbook
+    playbook = (
+        playbook
+        >> TEvent()
+        << TCommand()
+    )
+    assert playbook
+    assert len(playbook.actual) == len(playbook.playbook) == 4

mitmproxy/proxy/protocol2/test/tutils.py

@@ -3,11 +3,14 @@ import itertools
 import re
 import typing
 
+import copy
+
 from mitmproxy.proxy.protocol2 import commands
 from mitmproxy.proxy.protocol2 import events
 from mitmproxy.proxy.protocol2 import layer
 
-TPlaybook = typing.List[typing.Union[commands.Command, events.Event]]
+TPlaybookEntry = typing.Union[commands.Command, events.Event]
+TPlaybook = typing.List[TPlaybookEntry]
 
 
 def _eq(
@@ -60,9 +63,13 @@ class playbook:
     assert x2 == []
     """
     layer: layer.Layer
+    """The base layer"""
     playbook: TPlaybook
-    _asserted: int
+    """expected command/event sequence"""
     actual: TPlaybook
+    """actual command/event sequence"""
+    _final: bool
+    """True if no << or >> operation has been called on this."""
 
     def __init__(
             self,
@@ -77,25 +84,38 @@ class playbook:
         self.layer = layer
         self.playbook = playbook
         self.actual = []
-        self._asserted = 0
+        self._final = True
+
+    def _copy_with(self, entry: TPlaybookEntry):
+        self._final = False
+        p = playbook(
+            self.layer,
+            self.playbook + [entry]
+        )
+        p.actual = self.actual.copy()
+        return p
 
     def __rshift__(self, e):
         """Add an event to send"""
         assert isinstance(e, events.Event)
-        self.playbook.append(e)
-        return self
+        return self._copy_with(e)
 
     def __lshift__(self, c):
         """Add an expected command"""
         if c is None:
             return self
         assert isinstance(c, commands.Command)
-        self.playbook.append(c)
-        return self
+        return self._copy_with(c)
 
     def __bool__(self):
         """Determine if playbook is correct."""
-        for i, x in list(enumerate(self.playbook))[self._asserted:]:
+
+        self.layer = copy.deepcopy(self.layer)
+        self.playbook = copy.deepcopy(self.playbook)
+        self.actual = copy.deepcopy(self.actual)
+
+        already_asserted = len(self.actual)
+        for i, x in enumerate(self.playbook[already_asserted:], already_asserted):
             if isinstance(x, commands.Command):
                 pass
             else:
@@ -107,11 +127,10 @@ class playbook:
                 self.actual.extend(
                     self.layer.handle_event(x)
                 )
-        self._asserted = len(self.playbook)
 
         success = all(
             _eq(e, a)
-                for e, a in itertools.zip_longest(self.playbook, self.actual)
+            for e, a in itertools.zip_longest(self.playbook, self.actual)
         )
         if not success:
             def _str(x):
@@ -129,7 +148,7 @@ class playbook:
             return True
 
     def __del__(self):
-        if self._asserted < len(self.playbook):
+        if self._final and len(self.actual) < len(self.playbook):
             raise RuntimeError("Unfinished playbook!")
 
 
@@ -144,4 +163,4 @@ class Placeholder:
         return self.obj
 
     def __repr__(self):
-        return repr(self.obj)
+        return f"P({repr(self.obj)})"