"""Comprueba lo que los apuntes afirman sobre los programas de la semana 9.""" import pathlib import re import subprocess import tempfile import unittest HERE = pathlib.Path(__file__).parent BUILD = HERE / "build" FLAGS = ["-Wall", "-Wextra", "-std=c17"] def run(program, stdin=""): """Ejecuta un programa de build/; devuelve su salida (con errores) y su estado.""" done = subprocess.run( [str(BUILD / program)], input=stdin, text=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, timeout=10, ) return done.stdout, done.returncode def compile_demo(name, *extra): """Compila un programa de errors/; devuelve los mensajes, el estado y el ejecutable.""" out = pathlib.Path(tempfile.mkdtemp()) / name done = subprocess.run( ["gcc", *FLAGS, *extra, f"errors/{name}.c", "-o", str(out)], cwd=HERE, text=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, ) return done.stdout, done.returncode, out def run_binary(binary, stdin=""): done = subprocess.run( [str(binary)], input=stdin, text=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, timeout=10, ) return done.stdout, done.returncode class CleanCompile(unittest.TestCase): def test_examples_have_no_warnings(self): for source in sorted(HERE.glob("*.c")): with self.subTest(source=source.name): done = subprocess.run( ["gcc", *FLAGS, "-Werror", "-fsyntax-only", str(source)], text=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, ) self.assertEqual(done.returncode, 0, done.stdout) class Addresses(unittest.TestCase): def test_variable_addresses_show_sizes(self): out, status = run("variable_addresses") self.assertEqual(status, 0) self.assertRegex(out, r"age vale 19, ocupa \d+ bytes, está en 0x[0-9a-f]+\n") self.assertIn("average vale 14.5", out) self.assertIn("section vale A, ocupa 1 byte,", out) def test_elements_of_an_array_are_contiguous(self): out, status = run("array_addresses") self.assertEqual(status, 0) size = int(re.search(r"sizeof\(int\) = (\d+)", out).group(1)) addresses = [int(a, 16) for a in re.findall(r"está en 0x([0-9a-f]+)", out)] self.assertEqual(len(addresses), 4) for i, address in enumerate(addresses): self.assertEqual(address, addresses[0] + i * size) class Arrays(unittest.TestCase): def test_first_array(self): out, _ = run("first_array") self.assertEqual(out.split("\n")[1], "grades[1] = 12") self.assertEqual(out.split("\n")[4], "grades[4] = 19") def test_missing_initializers_are_zero(self): out, _ = run("array_init") self.assertIn("i = 2: full 4, partial 0, zeros 0", out) self.assertIn("i = 4: full 5, partial 0, zeros 0", out) def test_element_count_does_not_depend_on_int_size(self): out, _ = run("array_init") self.assertIn("elementos de full = 5", out) self.assertIn("elementos de counted = 3", out) def test_copy_is_independent(self): self.assertEqual(run("copy_array")[0], "original[0] = 5, copy[0] = 99\n") def test_assigning_an_array_does_not_compile(self): messages, status, _ = compile_demo("assign_array") self.assertNotEqual(status, 0) self.assertIn("assignment to expression with array type", messages) def test_comparing_arrays_warns_and_says_different(self): messages, status, binary = compile_demo("compare_arrays") self.assertEqual(status, 0) self.assertIn("-Warray-compare", messages) self.assertEqual(run_binary(binary)[0], "distintos\n") class Patterns(unittest.TestCase): def test_temperatures(self): self.assertEqual(run("temperatures"), ("Suma: 3\nPromedio: 0.43\nMayor: 4, en el día 2\n", 0)) def test_reverse(self): self.assertEqual(run("reverse", "3 10 20 30"), ("30\n20\n10\n", 0)) self.assertEqual(run("reverse", "1 7"), ("7\n", 0)) def test_reverse_full_array(self): values = list(range(100)) text = "100 " + " ".join(map(str, values)) expected = "".join(f"{v}\n" for v in reversed(values)) self.assertEqual(run("reverse", text), (expected, 0)) def test_reverse_rejects_what_does_not_fit(self): for n in [0, -1, 101, 200]: with self.subTest(n=n): self.assertEqual(run("reverse", f"{n} 1 2"), ("n debe estar entre 1 y 100\n", 1)) def test_reverse_bad_input(self): for text in ["", "abc", "3 10 20", "3 10 x"]: with self.subTest(text=text): self.assertEqual(run("reverse", text), ("Entrada inválida\n", 1)) def test_votes(self): out, status = run("votes", "1 2 2 3 7 2 0") self.assertEqual(status, 0) self.assertEqual(out, "Candidato 1: 1\nCandidato 2: 3\nCandidato 3: 1\nInválidos: 1\n") def test_votes_rejects_indexes_out_of_the_array(self): out, status = run("votes", "4 -1 100000 -100000 3 0") self.assertEqual(status, 0) self.assertEqual(out, "Candidato 1: 0\nCandidato 2: 0\nCandidato 3: 1\nInválidos: 4\n") def test_votes_bad_input(self): for text in ["", "abc", "1 2", "1 x"]: with self.subTest(text=text): self.assertEqual(run("votes", text), ("Entrada inválida\n", 1)) class OutOfBounds(unittest.TestCase): """Sin sanitizer no se compara nada: el resultado es comportamiento indefinido.""" def test_compiling_says_nothing(self): for name in ["off_by_one", "write_out", "fixed_constant"]: with self.subTest(name=name): messages, status, _ = compile_demo(name) self.assertEqual((messages, status), ("", 0)) def test_address_sanitizer_reports_the_read(self): messages, status, binary = compile_demo("off_by_one", "-g", "-fsanitize=address") self.assertEqual((messages, status), ("", 0)) out, status = run_binary(binary) self.assertNotEqual(status, 0) self.assertNotIn("grades[5] =", out) self.assertIn("stack-buffer-overflow", out) self.assertIn("READ of size 4", out) self.assertIn("errors/off_by_one.c:11", out) def test_address_sanitizer_reports_the_write_next_to_the_array(self): _, _, binary = compile_demo("write_out", "-g", "-fsanitize=address") out, status = run_binary(binary, "4") self.assertNotEqual(status, 0) self.assertIn("stack-buffer-overflow", out) self.assertIn("WRITE of size 4", out) def test_valid_index_gives_no_report(self): _, _, binary = compile_demo("write_out", "-g", "-fsanitize=address") self.assertEqual(run_binary(binary, "3"), ("values[3] = 99\nbefore = 111, after = 222\n", 0)) def test_undefined_sanitizer_checks_the_index(self): _, _, binary = compile_demo("write_out", "-g", "-fsanitize=address,undefined") out, status = run_binary(binary, "4") self.assertNotEqual(status, 0) self.assertIn("runtime error: index 4 out of bounds for type 'int [4]'", out) self.assertIn("stack-buffer-overflow", out) def test_debug_flag_adds_the_line_number(self): _, _, without_g = compile_demo("off_by_one", "-fsanitize=address") self.assertNotIn("errors/off_by_one.c:11", run_binary(without_g)[0]) class Assembly(unittest.TestCase): def test_the_sum_stays_in_the_assembly(self): # Una suma entre dos registros: add de tres operandos en ARM, addl de dos en x86-64. # Con -O2 el compilador calcula el resultado y la suma desaparece. sum_of_registers = r"\badd\s+w\d+, w\d+, w\d+|\baddl\s+%\w+, %\w+" folder = pathlib.Path(tempfile.mkdtemp()) for level, check in (("-O0", self.assertRegex), ("-O2", self.assertNotRegex)): target = folder / f"add_two{level}.s" subprocess.run(["gcc", "-S", level, "add_two.c", "-o", str(target)], cwd=HERE, check=True) check(target.read_text(), sum_of_registers) self.assertEqual(run("add_two")[0], "5\n") if __name__ == "__main__": unittest.main()