Teachers often need to identify students who may need extra support. In this challenge, you'll use a dictionary of grades to find and print the names of students with grades below 70.


import unittest
import user_code
import ast
import re   
import importlib
import csv
import unittest
import importlib
import io
from contextlib import redirect_stdout

class TestTask(unittest.TestCase):
    def test_prints_students_below_70(self):
        import user_code
        importlib.reload(user_code)
        grades = {
            "Alice": 85,
            "Bob": 67,
            "Charlie": 92,
            "Diana": 58,
            "Ethan": 74,
            "Fiona": 69
        }
        f = io.StringIO()
        with redirect_stdout(f):
            user_code.print_students_needing_improvement(grades)
        output = normalize_text(f.getvalue())
        _dynamic_test(
            self,
            "bob" in output and "diana" in output and "fiona" in output,
            "Prints all students with grades below 70",
            f"Expected to print Bob, Diana, Fiona. Output: {output}",
        )
        _dynamic_test(
            self,
            "alice" not in output and "charlie" not in output and "ethan" not in output,
            "Does not print students with grades 70 or above",
            f"Should not print Alice, Charlie, Ethan. Output: {output}",
        )

    def test_empty_dict(self):
        import user_code
        importlib.reload(user_code)
        grades = {}
        f = io.StringIO()
        with redirect_stdout(f):
            user_code.print_students_needing_improvement(grades)
        output = normalize_text(f.getvalue())
        _dynamic_test(
            self,
            output.strip() == "",
            "Handles empty dictionary without error and prints nothing",
            f"Expected no output for empty dictionary. Got: {output}",
        )

    def test_all_above_70(self):
        import user_code
        importlib.reload(user_code)
        grades = {
            "Alice": 85,
            "Charlie": 92,
            "Ethan": 74
        }
        f = io.StringIO()
        with redirect_stdout(f):
            user_code.print_students_needing_improvement(grades)
        output = normalize_text(f.getvalue())
        _dynamic_test(
            self,
            output.strip() == "",
            "Prints nothing when all students have grades 70 or above",
            f"Expected no output. Got: {output}",
        )

    def test_all_below_70(self):
        import user_code
        importlib.reload(user_code)
        grades = {
            "Bob": 67,
            "Diana": 58,
            "Fiona": 69
        }
        f = io.StringIO()
        with redirect_stdout(f):
            user_code.print_students_needing_improvement(grades)
        output = normalize_text(f.getvalue())
        _dynamic_test(
            self,
            "bob" in output and "diana" in output and "fiona" in output,
            "Prints all names when all students are below 70",
            f"Expected Bob, Diana, Fiona in output. Got: {output}",
        )

def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)

def normalize_text(text):
    text = text.lower()
    text = re.sub(r"\\s{2,}", " ", text)
    text = re.sub(r"\\s*([,:?])\\s*", r"\\1 ", text)
    return text.strip()

def change_var(code: str, var_name: str, value: str) -> str:
    tree = ast.parse(code)
    lines = code.splitlines()
    changed = False
    # Collect all assignment nodes to modify
    assign_nodes = [
        (i, node)
        for i, node in enumerate(tree.body)
        if isinstance(node, ast.Assign)
        and any(isinstance(target, ast.Name) and target.id == var_name for target in node.targets)
    ]

    # If nothing to change, return unmodified code
    if not assign_nodes:
        return code

    # Perform replacements for all matching assignments (from last to first to not break line offsets)
    for i, node in reversed(assign_nodes):
        start_line = node.lineno - 1
        line = lines[start_line]
        indent = ' ' * (len(line) - len(line.lstrip()))
        lines[start_line] = f"{indent}{var_name} = {value}"
        next_line = len(lines)
        for next_node in tree.body[i+1:]:
            if hasattr(next_node, 'lineno'):
                next_line = next_node.lineno - 1
                break
        if next_line > start_line + 1:
            lines[start_line+1:next_line] = []
        changed = True

    return '\\n'.join(lines) if changed else code

if __name__ == "__main__":
    unittest.main()


test_main.py

A beginner-friendly Python course designed specifically for teachers. Learn how to use Python to organize grades, analyze student performance, and automate classroom tasks with engaging, real-world examples.

Learn the basics of Python programming with a focus on classroom and grade organization. This section introduces Python syntax, variables, and simple data structures through relatable educational scenarios.

Dive deeper into Python by learning how to organize, analyze, and visualize student grades. This section covers dictionaries, conditional logic, and basic data analysis techniques tailored for teachers.

Explore how Python can automate common classroom tasks such as attendance tracking, assignment management, and generating reports. This section introduces file operations and more advanced automation techniques.

Challenge: Find Students Needing Improvement

解答