testserver.AsyncTestServerSession

testserver.AsyncTestServerSession(
    app=None,
    *,
    client_data=None,
    timeout_secs=5.0,
)

An in-memory Shiny session driven from async test code.

Construct one with test_server_async rather than directly. The session runs the app's server function against a mock connection — no browser and no network server — so inputs can be set and outputs asserted in process.

Use it as an async context manager to keep the session alive across several user interactions:

async with test_server_async(server) as session:
    await session.set_inputs(x=10)
    assert session.outputs["doubled"] == "20"

async with is the only supported way to run a session: it starts the app on entry and always tears it down on exit, including when the test fails. Values registered with shiny.testmode.export_test_values are read with get_export.

See Also

• test_server_async
• TestServerSession
• TestServerValues

Attributes

Name	Description
error	A summary of the first error, or None when is_ok is True.
is_ok	True when nothing errored and no fatal error occurred.
ns	The namespace these ids are read in; Root ("") for a session.

Methods

Name	Description
flush	Re-read the session’s output, export, and error values.
get_export	Return one exported test value.
get_input	Return one input value.
get_output	Return one output value.
keys	Return the keys dict(session) produces. See TestServerValues.
make_scope	Return a view of this session namespaced to a module instance.
root_scope	Return this session, which is already the root.
set_inputs	Set input values and wait for the resulting reactive flush.
to_values	Capture the session’s current state.

flush

testserver.AsyncTestServerSession.flush()

Re-read the session's output, export, and error values.

set_inputs already does this, so an explicit call is only needed after something outside the test changes reactive state (for example an effect driven by a timer).

Returns

Name	Type	Description
	AsyncTestServerSession	This session, so calls can be chained.

get_export

testserver.AsyncTestServerSession.get_export(name)

Return one exported test value.

Parameters

Name	Type	Description	Default
name	str	A name passed to shiny.testmode.export_test_values.	required

Returns

Name	Type	Description
	TestServerValue	A TestServerValue. It compares equal to the value itself, so session.get_export("doubled") == 40 works.

Raises

Name	Type	Description
	KeyError	If that name was not exported.

get_input

testserver.AsyncTestServerSession.get_input(name)

Return one input value.

Parameters

Name	Type	Description	Default
name	str	An input id.	required

Returns

Name	Type	Description
	TestServerValue	A TestServerValue. It compares equal to the value itself, so session.get_input("n") == 10 works.

Raises

Name	Type	Description
	KeyError	If the session has not received that input.

get_output

testserver.AsyncTestServerSession.get_output(name)

Return one output value.

Parameters

Name	Type	Description	Default
name	str	An output id.	required

Returns

Name	Type	Description
	TestServerValue	A TestServerValue, with status "silent" if the output’s latest render produced nothing. It compares equal to the value itself, so session.get_output("txt") == "hi" works.

Raises

Name	Type	Description
	KeyError	If the app has no such output.

keys

testserver.AsyncTestServerSession.keys()

Return the keys dict(session) produces. See TestServerValues.

make_scope

testserver.AsyncTestServerSession.make_scope(id)

Return a view of this session namespaced to a module instance.

Mirrors shiny.Session.make_scope: inside a module the app's server code uses bare ids, and so does the returned view, while the session underneath keeps the namespaced ones.

Parameters

Name	Type	Description	Default
id	str	The id the module instance was given, as in counter_server("counter").	required

Returns

Name	Type	Description
	AsyncTestServerScope	An AsyncTestServerScope reading and writing the same live session.

See Also

• AsyncTestServerScope

root_scope

testserver.AsyncTestServerSession.root_scope()

Return this session, which is already the root.

Mirrors shiny.Session.root_scope, so code handed either a session or an AsyncTestServerScope can reach the session without a type check.

set_inputs

testserver.AsyncTestServerSession.set_inputs(**kwargs)

Set input values and wait for the resulting reactive flush.

Simulates a user interaction: the values are sent to the session as an input update, and the call returns once the reactive graph has settled and the values read by get_input, get_output, and get_export have been refreshed.

Parameters

Name	Type	Description	Default
**kwargs	Any	Input values keyed by input id. Ids that are not valid Python identifiers – a module’s namespaced "counter-n", say – go through an unpacked dictionary: set_inputs(**{"counter-n": 7}).	{}

Returns

Name	Type	Description
	AsyncTestServerSession	This session, so calls can be chained.

Raises

Name	Type	Description
	TimeoutError	If the flush does not complete within timeout_secs.
	RuntimeError	If the session is not running, or has already ended because of a fatal error.

to_values

testserver.AsyncTestServerSession.to_values()

Capture the session's current state.

Returns

Name	Type	Description
	TestServerValues	A TestServerValues snapshot of copies, which stays valid after the session is closed.