def has_printout(state,
index,
not_printed_msg=None,
pre_code=None,
name=None,
copy=False):
"""Check if the right printouts happened.
``has_printout()`` will look for the printout in the solution code that you specified with ``index`` (0 in this case), rerun the ``print()`` call in
the solution process, capture its output, and verify whether the output is present in the output of the student.
This is more robust as ``Ex().check_function('print')`` initiated chains as students can use as many
printouts as they want, as long as they do the correct one somewhere.
Args:
index (int): index of the ``print()`` call in the solution whose output you want to search for in the student output.
not_printed_msg (str): if specified, this overrides the default message that is generated when the output
is not found in the student output.
pre_code (str): Python code as a string that is executed before running the targeted student call.
This is the ideal place to set a random seed, for example.
copy (bool): whether to try to deep copy objects in the environment, such as lists, that could
accidentally be mutated. Disabled by default, which speeds up SCTs.
state (State): state as passed by the SCT chain. Don't specify this explicitly.
:Example:
Suppose you want somebody to print out 4: ::
print(1, 2, 3, 4)
The following SCT would check that: ::
Ex().has_printout(0)
All of the following SCTs would pass: ::
print(1, 2, 3, 4)
print('1 2 3 4')
print(1, 2, '3 4')
print("random"); print(1, 2, 3, 4)
:Example:
Watch out: ``has_printout()`` will effectively **rerun** the ``print()`` call in the solution process after the entire solution script was executed.
If your solution script updates the value of `x` after executing it, ``has_printout()`` will not work.
Suppose you have the following solution: ::
x = 4
print(x)
x = 6
The following SCT will not work: ::
Ex().has_printout(0)
Why? When the ``print(x)`` call is executed, the value of ``x`` will be 6, and pythonwhat will look for the output `'6`' in the output the student generated.
In cases like these, ``has_printout()`` cannot be used.
:Example:
Inside a for loop ``has_printout()``
Suppose you have the following solution: ::
for i in range(5):
print(i)
The following SCT will not work: ::
Ex().check_for_loop().check_body().has_printout(0)
The reason is that ``has_printout()`` can only be called from the root state. ``Ex()``.
If you want to check printouts done in e.g. a for loop, you have to use a `check_function('print')` chain instead: ::
Ex().check_for_loop().check_body().\\
set_context(0).check_function('print').\\
check_args(0).has_equal_value()
"""
extra_msg = "If you want to check printouts done in e.g. a for loop, you have to use a `check_function('print')` chain instead."
state.assert_execution_root("has_printout", extra_msg=extra_msg)
if not_printed_msg is None:
not_printed_msg = (
"Have you used `{{sol_call}}` to do the appropriate printouts?")
try:
sol_call_ast = state.ast_dispatcher.find(
"function_calls", state.solution_ast)["print"][index]["node"]
except (KeyError, IndexError):
raise InstructorError.from_message(
"`has_printout({})` couldn't find the {} print call in your solution."
.format(index, get_ord(index + 1)))
out_sol, str_sol = getOutputInProcess(
tree=sol_call_ast,
process=state.solution_process,
context=state.solution_context,
env=state.solution_env,
pre_code=pre_code,
copy=copy,
)
sol_call_str = state.solution_ast_tokens.get_text(sol_call_ast)
if isinstance(str_sol, Exception):
with debugger(state):
state.report(
"Evaluating the solution expression {} raised error in solution process."
"Error: {} - {}".format(sol_call_str, type(out_sol), str_sol))
has_output(
state,
out_sol.strip(),
pattern=False,
no_output_msg=FeedbackComponent(not_printed_msg,
{"sol_call": sol_call_str}),
)
return state
def has_printout(index,
not_printed_msg=None,
pre_code=None,
name=None,
copy=False,
state=None):
"""Check if the output of print() statement in the solution is in the output the student generated.
This is more robust as ``Ex().check_function('print')`` initiated chains as students can use as many
printouts as they want, as long as they do the correct one somewhere.
.. note::
When zooming in on parts of the student submission (with e.g. ``check_for_loop()``), we are not
zooming in on the piece of the student output that is related to that piece of the student code.
In other words, ``has_printout()`` always considers the entire student output.
Args:
index (int): index of the ``print()`` call in the solution whose output you want to search for in the student output.
not_printed_msg (str): if specified, this overrides the default message that is generated when the output
is not found in the student output.
pre_code (str): Python code as a string that is executed before running the targeted student call.
This is the ideal place to set a random seed, for example.
copy (bool): whether to try to deep copy objects in the environment, such as lists, that could
accidentally be mutated. Disabled by default, which speeds up SCTs.
state (State): state as passed by the SCT chain. Don't specify this explicitly.
:Example:
Solution::
print(1, 2, 3, 4)
SCT::
Ex().has_printout(0)
Each of these submissions will pass::
print(1, 2, 3, 4)
print('1 2 3 4')
print(1, 2, '3 4')
print("random"); print(1, 2, 3, 4)
"""
if not_printed_msg is None:
not_printed_msg = "__JINJA__:Have you used `{{sol_call}}` to do the appropriate printouts?"
try:
sol_call_ast = state.solution_function_calls['print'][index]['node']
except (KeyError, IndexError):
raise ValueError(
"Using has_printout() with index {} expects that there is/are at least {} print() call(s) in your solution."
"Is that the case?".format(index, index + 1))
out_sol, str_sol = getOutputInProcess(tree=sol_call_ast,
process=state.solution_process,
context=state.solution_context,
env=state.solution_env,
pre_code=pre_code,
copy=copy)
sol_call_str = state.solution_tree_tokens.get_text(sol_call_ast)
if isinstance(str_sol, Exception):
raise ValueError(
"Evaluating the solution expression {} raised error in solution process."
"Error: {} - {}".format(sol_call_str, type(out_sol), str_sol))
_msg = state.build_message(not_printed_msg, {'sol_call': sol_call_str})
has_output(out_sol.strip(), pattern=False, no_output_msg=_msg, state=state)
return state
