debuglink: add null debuglink, allow running tests interactively

run with:
INTERACT=1 pytest <your options here>

trezorlib/debuglink.py

@@ -26,8 +26,9 @@ EXPECTED_RESPONSES_CONTEXT_LINES = 3
 
 
 class DebugLink:
-    def __init__(self, transport):
+    def __init__(self, transport, auto_interact=True):
         self.transport = transport
+        self.allow_interactions = auto_interact
 
     def open(self):
         self.transport.begin_session()
@@ -87,6 +88,8 @@ class DebugLink:
         return obj.passphrase_protection
 
     def input(self, word=None, button=None, swipe=None):
+        if not self.allow_interactions:
+            return
         decision = proto.DebugLinkDecision()
         if button is not None:
             decision.yes_no = button
@@ -130,6 +133,24 @@ class DebugLink:
         self._call(proto.DebugLinkFlashErase(sector=sector), nowait=True)
 
 
+class NullDebugLink(DebugLink):
+    def __init__(self):
+        super().__init__(None)
+
+    def open(self):
+        pass
+
+    def close(self):
+        pass
+
+    def _call(self, msg, nowait=False):
+        if not nowait:
+            if isinstance(msg, proto.DebugLinkGetState):
+                return proto.DebugLinkState()
+            else:
+                raise RuntimeError("unexpected call to a fake debuglink")
+
+
 class DebugUI:
     INPUT_FLOW_DONE = object()
 
@@ -171,8 +192,16 @@ class TrezorClientDebugLink(TrezorClient):
     # without special DebugLink interface provided
     # by the device.
 
-    def __init__(self, transport):
-        self.debug = DebugLink(transport.find_debug())
+    def __init__(self, transport, auto_interact=True):
+        try:
+            debug_transport = transport.find_debug()
+            self.debug = DebugLink(debug_transport, auto_interact)
+        except Exception:
+            if not auto_interact:
+                self.debug = NullDebugLink()
+            else:
+                raise
+
         self.ui = DebugUI(self.debug)
 
         self.in_with_statement = 0

trezorlib/tests/device_tests/common.py

@@ -15,7 +15,6 @@
 # If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
 
 from trezorlib import debuglink, device
-from trezorlib.debuglink import TrezorClientDebugLink
 from trezorlib.messages.PassphraseSourceType import HOST as PASSPHRASE_ON_HOST
 
 from . import conftest
@@ -35,8 +34,7 @@ class TrezorTest:
     pin8 = "45678978"
 
     def setup_method(self, method):
-        wirelink = conftest.get_device()
-        self.client = TrezorClientDebugLink(wirelink)
+        self.client = conftest.get_device()
         # self.client.set_buttonwait(3)
 
         device.wipe(self.client)

trezorlib/tests/device_tests/conftest.py

@@ -30,20 +30,26 @@ TREZOR_VERSION = None
 def get_device():
     path = os.environ.get("TREZOR_PATH")
     if path:
-        return get_transport(path)
+        transport = get_transport(path)
     else:
         devices = enumerate_devices()
         for device in devices:
             if hasattr(device, "find_debug"):
-                return device
+                transport = device
+                break
+        else:
             raise RuntimeError("No debuggable device found")
+    env_interactive = int(os.environ.get("INTERACT", 0))
+    try:
+        return TrezorClientDebugLink(transport, auto_interact=not env_interactive)
+    except Exception as e:
+        raise RuntimeError(
+            "Failed to open debuglink for {}".format(transport.get_path())
+        ) from e
 
 
 def device_version():
-    device = get_device()
-    if not device:
-        raise RuntimeError()
-    client = TrezorClientDebugLink(device)
+    client = get_device()
     if client.features.model == "T":
         return 2
     else:
@@ -52,8 +58,7 @@ def device_version():
 
 @pytest.fixture(scope="function")
 def client():
-    wirelink = get_device()
-    client = TrezorClientDebugLink(wirelink)
+    client = get_device()
     wipe_device(client)
 
     client.open()
@@ -100,6 +105,11 @@ def pytest_addoption(parser):
         "args",
         [],
     )
+    parser.addoption(
+        "--interactive",
+        action="store_true",
+        help="Wait for user to do interaction manually",
+    )
 
 
 def pytest_runtest_setup(item):