double v0.7.0 Double View Source
Double builds on-the-fly injectable dependencies for your tests. It does NOT override behavior of existing modules or functions. Double uses Elixir's built-in language features such as pattern matching and message passing to give you everything you would normally need a complex mocking tool for.
Link to this section Summary
Functions
Adds a stubbed function to the given map, struct, or module. Structs will fail if they are missing the key given for function_name. Modules will fail if the function is not defined.
Returns a specification to start this module under a supervisor.
Clears stubbed functions from a double. By passing no arguments (or nil) all functions will be cleared. A single function name (atom) or a list of function names can also be given.
Returns a map that can be used to setup stubbed functions.
Same as double/0 but can return structs and modules too
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
Link to this section Types
allow_option() View Source
double_option()
View Source
double_option() :: {:verify, true | false}
double_option() :: {:verify, true | false}
Link to this section Functions
allow(dbl, function_name) View Source
Adds a stubbed function to the given map, struct, or module. Structs will fail if they are missing the key given for function_name. Modules will fail if the function is not defined.
allow(dbl, function_name, func_opts) View Source
child_spec(init_arg) View Source
Returns a specification to start this module under a supervisor.
See Supervisor
.
clear(dbl, function_name \\ nil) View Source
Clears stubbed functions from a double. By passing no arguments (or nil) all functions will be cleared. A single function name (atom) or a list of function names can also be given.
double()
View Source
double() :: map()
double() :: map()
Returns a map that can be used to setup stubbed functions.
double(source, opts \\ [verify: true, send_stubbed_module: false])
View Source
double(struct(), [double_option()]) :: struct()
double(atom(), [double_option()]) :: atom()
double(struct(), [double_option()]) :: struct()
double(atom(), [double_option()]) :: atom()
Same as double/0 but can return structs and modules too
init(list) View Source
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
init_arg
is the argument term (second argument) passed to start_link/3
.
Returning {:ok, state}
will cause start_link/3
to return
{:ok, pid}
and the process to enter its loop.
Returning {:ok, state, timeout}
is similar to {:ok, state}
except handle_info(:timeout, state)
will be called after timeout
milliseconds if no messages are received within the timeout.
Returning {:ok, state, :hibernate}
is similar to {:ok, state}
except the process is hibernated before entering the loop. See
c:handle_call/3
for more information on hibernation.
Returning {:ok, state, {:continue, continue}}
is similar to
{:ok, state}
except that immediately after entering the loop
the c:handle_continue/2
callback will be invoked with the value
continue
as first argument.
Returning :ignore
will cause start_link/3
to return :ignore
and
the process will exit normally without entering the loop or calling
c:terminate/2
. If used when part of a supervision tree the parent
supervisor will not fail to start nor immediately try to restart the
GenServer
. The remainder of the supervision tree will be started
and so the GenServer
should not be required by other processes.
It can be started later with Supervisor.restart_child/2
as the child
specification is saved in the parent supervisor. The main use cases for
this are:
- The
GenServer
is disabled by configuration but might be enabled later. - An error occurred and it will be handled by a different mechanism than the
Supervisor
. Likely this approach involves callingSupervisor.restart_child/2
after a delay to attempt a restart.
Returning {:stop, reason}
will cause start_link/3
to return
{:error, reason}
and the process to exit with reason reason
without
entering the loop or calling c:terminate/2
.
Callback implementation for GenServer.init/1
.