In QA engineering, **visual summaries** such as charts are powerful tools for quickly communicating the outcomes of test executions to both technical and non-technical stakeholders. **Pie charts**, in particular, are effective for illustrating the proportion of passed and failed tests, making it easy to spot issues at a glance and prioritize further investigation. In this challenge, you will practice your data visualization skills by creating a pie chart that displays the distribution of test statuses from a static list.


import unittest
import user_code
import ast
import re   
import importlib
import csv
import unittest
import importlib
import matplotlib
matplotlib.use('Agg')  # Use non-interactive backend for testing
import matplotlib.pyplot as plt
import user_code

class TestTask(unittest.TestCase):
    def setUp(self):
        self.test_statuses = ["passed", "failed", "passed", "passed", "failed", "passed", "failed", "passed", "passed", "failed"]
        self.expected_counts = (6, 4)  # passed, failed
        # Patch plt.show to prevent actual chart popup
        self._original_show = plt.show
        plt.show = lambda: None

    def tearDown(self):
        plt.show = self._original_show

    def test_counts_correct(self):
        # Test that function counts passed/failed correctly
        importlib.reload(user_code)
        func = getattr(user_code, "plot_test_status_pie", None)
        _dynamic_test(
            self,
            callable(func),
            "plot_test_status_pie is defined as a function",
            "plot_test_status_pie is not defined or not callable",
        )
        # Patch plt.pie to capture input
        captured = {}
        def fake_pie(counts, labels=None, colors=None, autopct=None, startangle=None, explode=None):
            captured["counts"] = counts
            captured["labels"] = labels
            captured["colors"] = colors
            captured["autopct"] = autopct
            captured["startangle"] = startangle
            captured["explode"] = explode
            return [None, None, None]
        orig_pie = plt.pie
        plt.pie = fake_pie
        try:
            func(self.test_statuses)
        finally:
            plt.pie = orig_pie
        expected = [self.expected_counts[0], self.expected_counts[1]]
        _dynamic_test(
            self,
            "counts" in captured and captured["counts"] == expected,
            f"Counts passed to pie are correct: {expected}",
            f"Counts passed to pie are incorrect. Expected {expected}, got {captured.get('counts')}",
        )

    def test_labels_and_colors(self):
        importlib.reload(user_code)
        func = getattr(user_code, "plot_test_status_pie", None)
        captured = {}
        def fake_pie(counts, labels=None, colors=None, autopct=None, startangle=None, explode=None):
            captured["labels"] = labels
            captured["colors"] = colors
            return [None, None, None]
        orig_pie = plt.pie
        plt.pie = fake_pie
        try:
            func(self.test_statuses)
        finally:
            plt.pie = orig_pie
        _dynamic_test(
            self,
            "labels" in captured and isinstance(captured["labels"], list) and "Passed" in captured["labels"] and "Failed" in captured["labels"],
            "Pie chart labels include 'Passed' and 'Failed'",
            f"Pie chart labels missing or incorrect: {captured.get('labels')}",
        )
        _dynamic_test(
            self,
            "colors" in captured and isinstance(captured["colors"], list) and len(set(captured["colors"])) == 2,
            "Pie chart uses two different colors",
            f"Pie chart colors missing or not two distinct values: {captured.get('colors')}",
        )

    def test_percentage_labels(self):
        importlib.reload(user_code)
        func = getattr(user_code, "plot_test_status_pie", None)
        captured = {}
        def fake_pie(counts, labels=None, colors=None, autopct=None, startangle=None, explode=None):
            captured["autopct"] = autopct
            return [None, None, None]
        orig_pie = plt.pie
        plt.pie = fake_pie
        try:
            func(self.test_statuses)
        finally:
            plt.pie = orig_pie
        _dynamic_test(
            self,
            "autopct" in captured and "%" in str(captured["autopct"]),
            "Pie chart displays percentage labels",
            f"Pie chart autopct missing or not showing percentages: {captured.get('autopct')}",
        )

    def test_title_and_equal_aspect(self):
        importlib.reload(user_code)
        func = getattr(user_code, "plot_test_status_pie", None)
        captured = {"title": None, "aspect": None}
        orig_title = plt.title
        orig_axis = plt.axis
        def fake_title(val):
            captured["title"] = val
        def fake_axis(val):
            captured["aspect"] = val
        plt.title = fake_title
        plt.axis = fake_axis
        try:
            func(self.test_statuses)
        finally:
            plt.title = orig_title
            plt.axis = orig_axis
        _dynamic_test(
            self,
            normalize_text(captured["title"] or "") == normalize_text("Test Status Distribution"),
            "Chart title set to 'Test Status Distribution'",
            f"Chart title incorrect or missing: {captured['title']}",
        )
        _dynamic_test(
            self,
            captured["aspect"] == "equal",
            "Chart aspect ratio set to equal",
            f"Chart aspect not set to 'equal': {captured['aspect']}",
        )

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

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Challenge: Visualize Test Status Distribution

Solution

Challenge: Visualize Test Status Distribution

Solution