Add test_download_submission_autoresume_fail, which makes sure that i…

…n the event of a timeout that doesn't auto-resume, a RequestTimeoutError is ultimately thrown.

I added `__reduce__` methods to the custom exceptions because otherwise an exception was thrown when VCR tried to deepcopy them.

client/securedrop_client/sdk/__init__.py

@@ -44,6 +44,9 @@ class RequestTimeoutError(Exception):
     def __init__(self) -> None:
         super().__init__("The request timed out.")
 
+    def __reduce__(self):
+        return (self.__class__, ())
+
 
 class ServerConnectionError(Exception):
     """
@@ -53,6 +56,9 @@ class ServerConnectionError(Exception):
     def __init__(self) -> None:
         super().__init__("Cannot connect to the server.")
 
+    def __reduce__(self):
+        return (self.__class__, ())
+
 
 @dataclass(frozen=True)
 class StreamedResponse:

client/tests/sdk/test_api.py

@@ -288,6 +288,36 @@ def wait(self):
         # Restore Popen
         subprocess.Popen = OriginalPopen
 
+    @VCRAPI.use_cassette
+    def test_download_submission_autoresume_fail(self):
+        # Get a submision
+        submissions = self.api.get_all_submissions()
+        for s in submissions:
+            if s.is_file():
+                submission = s
+                break
+
+        # Stub subprocess.Popen to raise a subprocess.TimeoutExpired every time
+        class StubbedPopen(subprocess.Popen):
+            def __init__(self, *args, content="", **kwargs):
+                super().__init__(*args, **kwargs)
+
+                # Only stub if the command contains "securedrop.Proxy" or "securedrop-proxy"
+                cmd = shlex.join(args[0])
+                if "securedrop.Proxy" in cmd or "securedrop-proxy" in cmd:
+                    raise subprocess.TimeoutExpired(
+                        cmd=None, timeout=None, output=None, stderr=None
+                    )
+
+        OriginalPopen = subprocess.Popen
+        subprocess.Popen = StubbedPopen
+
+        # Download with the stubbed Popen
+        with pytest.raises(RequestTimeoutError):
+            self.api.download_submission(submission, "")
+
+        subprocess.Popen = OriginalPopen
+
     # ORDER MATTERS: The following tests add or delete data, and should
     # not be run before other tests, which may rely on the original fixture
     # state.