"""Comprueba lo que los apuntes afirman sobre los programas de la semana 11.""" import pathlib import re import subprocess import tempfile import unittest HERE = pathlib.Path(__file__).parent BUILD = HERE / "build" FLAGS = ["-Wall", "-Wextra", "-std=c17"] SANITIZE = ["-g", "-fsanitize=address,undefined"] def execute(command, stdin=""): done = subprocess.run( command, input=stdin, encoding="utf-8", errors="replace", stdout=subprocess.PIPE, stderr=subprocess.STDOUT, timeout=10, ) return done.stdout, done.returncode def run(program, stdin=""): """Ejecuta un programa de build/; devuelve su salida (con errores) y su estado.""" return execute([str(BUILD / program)], stdin) def build_source(source, *extra): """Compila un archivo; devuelve los mensajes, el estado y el ejecutable.""" out = pathlib.Path(tempfile.mkdtemp()) / pathlib.Path(source).stem done = subprocess.run( ["gcc", *FLAGS, *extra, source, "-o", str(out)], cwd=HERE, encoding="utf-8", stdout=subprocess.PIPE, stderr=subprocess.STDOUT, ) return done.stdout, done.returncode, out class CleanCompile(unittest.TestCase): def test_examples_have_no_warnings(self): # Se compila de verdad: -Wstringop-truncation no sale solo revisando la sintaxis. for source in sorted(HERE.glob("*.c")): with self.subTest(source=source.name): messages, status, _ = build_source( source.name, *SANITIZE, "-Werror", *(["-c"] if source.name == "check_lab.c" else [])) self.assertEqual(status, 0, messages) def test_no_pointer_variables_or_pointer_arithmetic_in_examples(self): # La GUIA deja los punteros para cursos posteriores. for source in sorted(HERE.glob("*.c")) + sorted((HERE / "solution").glob("*.c")): if source.name == "check_lab.c": continue code = re.sub(r"//[^\n]*", "", source.read_text(encoding="utf-8")) with self.subTest(source=source.name): self.assertNotRegex(code, r"\b(?:char|int|double)\s*\*\s*\w") self.assertNotRegex(code, r"str(?:str|chr)\([^;]*\)\s*[-+]") class Lengths(unittest.TestCase): def test_lengths(self): self.assertEqual(run("lengths"), ( 'strlen(t) = 4\nsizeof(t) = 8\nstrlen("") = 0\nstrlen("año") = 4\naloh\n', 0)) def test_subtracting_from_zero_wraps(self): messages, status, binary = build_source("errors/strlen_wrap.c") self.assertEqual(status, 0) self.assertIn("-Wtype-limits", messages) output, _ = execute([str(binary)]) value = int(re.search(r"= (\d+)", output).group(1)) self.assertGreater(value, 2 ** 31) # el valor exacto depende del tamaño de size_t self.assertEqual((value + 1) & value, 0) # es 2^n - 1 self.assertIn("siempre se cumple", output) def test_last_char_of_empty_string_is_reported(self): messages, status, binary = build_source("errors/last_char.c", *SANITIZE) self.assertEqual(status, 0) self.assertEqual(messages, "") # gcc no avisa output, code = execute([str(binary)]) self.assertIn("AddressSanitizer", output) self.assertNotEqual(code, 0) def test_sign_compare_warning(self): messages, status, _ = build_source("errors/sign_compare.c") self.assertEqual(status, 0) self.assertIn("-Wsign-compare", messages) class Comparing(unittest.TestCase): def test_equal_arrays(self): messages, status, binary = build_source("errors/equal_arrays.c") self.assertEqual(status, 0) self.assertIn("-Warray-compare", messages) self.assertEqual(execute([str(binary)]), ("distintas\n", 0)) def test_equal_params_is_silent(self): messages, status, binary = build_source("errors/equal_params.c") self.assertEqual((messages, status), ("", 0)) self.assertEqual(execute([str(binary)]), ("a con b: 0\na con a: 1\n", 0)) def test_equal_literals_warns_and_its_result_is_not_tested(self): messages, status, binary = build_source("errors/equal_literals.c") self.assertEqual(status, 0) self.assertIn("unspecified behavior", messages) output, _ = execute([str(binary)]) self.assertIn(output, ("0\n", "1\n")) def test_strcmp_order(self): output, code = run("compare") self.assertEqual(code, 0) self.assertEqual(output.splitlines(), [ '"ana" y "ana" son iguales', '"ana" va antes que "ano"', '"an" va antes que "ana"', '"sol" va después de "luna"', '"Z" va antes que "a"', '"z" va antes que "ñ"', ]) def test_strcmp_order_does_not_depend_on_char_signedness(self): expected, _ = run("compare") for option in ["-fsigned-char", "-funsigned-char"]: with self.subTest(option=option): _, status, binary = build_source("compare.c", option) self.assertEqual(status, 0) self.assertEqual(execute([str(binary)]), (expected, 0)) def test_strcmp_in_an_if_reads_backwards(self): _, status, binary = build_source("errors/strcmp_wrong.c") self.assertEqual(status, 0) self.assertEqual(execute([str(binary)]), ("distintas\n", 0)) class Copying(unittest.TestCase): def test_strncpy_bytes(self): output, code = run("strncpy_bytes") self.assertEqual(code, 0) rows = [line.split() for line in output.splitlines()] self.assertEqual(rows[0], ["115", "111", "108", "0", "0"]) # sol, con relleno self.assertEqual(rows[1], ["108", "117", "110", "97", "0"]) # luna, justo self.assertEqual(rows[2], ["101", "115", "116", "114", "101"]) # sin '\0' self.assertNotIn("0", rows[2]) def test_gcc_warns_only_when_it_sees_the_text(self): messages, status, _ = build_source("errors/strncpy_warn.c") self.assertEqual(status, 0) self.assertIn("-Wstringop-truncation", messages) messages, status, _ = build_source("errors/strncpy_no_null.c") self.assertEqual((messages, status), ("", 0)) def test_strncpy_without_terminator_is_reported(self): _, status, binary = build_source("errors/strncpy_no_null.c", *SANITIZE) self.assertEqual(status, 0) output, code = execute([str(binary)]) self.assertIn("AddressSanitizer: stack-buffer-overflow", output) self.assertIn("READ of size", output) self.assertNotEqual(code, 0) def test_safe_copy(self): self.assertEqual(run("safe_copy"), ("sol\nluna\nestr\n", 0)) def test_append(self): self.assertEqual(run("append"), ("Ana Quispe\nAna Qui\n", 0)) def test_strcat_overflows_only_with_long_input(self): messages, status, binary = build_source("errors/strcat_overflow.c", *SANITIZE) self.assertEqual((messages, status), ("", 0)) self.assertEqual(execute([str(binary)], "Li\n"), ("Ana Li\n", 0)) output, code = execute([str(binary)], "Quispe_Huaman\n") self.assertIn("AddressSanitizer: stack-buffer-overflow", output) self.assertIn("WRITE of size 14", output) self.assertNotEqual(code, 0) self.assertEqual(execute([str(binary)], ""), ("Entrada inválida\n", 1)) def test_strcat_overlap(self): messages, status, binary = build_source("errors/strcat_overlap.c", *SANITIZE) self.assertEqual(status, 0) self.assertIn("-Wrestrict", messages) output, code = execute([str(binary)]) self.assertIn("strcat-param-overlap", output) self.assertNotEqual(code, 0) class Searching(unittest.TestCase): def test_find_text(self): self.assertEqual(run("find_text"), ( "Tiene @: @example.com\nNo tiene #\nDesde Lima: Lima\n" "lima, en minúsculas, no aparece\nDesde la ñ: ño pasado llovió en Lima\n" "Desde el byte 3: año pasado llovió en Lima\n" "Desde el byte 0 hay un el\nDesde el byte 1 no hay ninguno\n", 0)) def test_null_result_used_without_checking_does_not_exit_cleanly(self): # Es comportamiento indefinido: no se prueba cómo muere, solo con el sanitizer. _, status, binary = build_source("errors/strstr_null.c", *SANITIZE) self.assertEqual(status, 0) output, code = execute([str(binary)]) self.assertNotEqual(code, 0) self.assertIn("null", output) class Matrices(unittest.TestCase): def test_layout_sizes(self): output, code = run("matrix_layout") self.assertEqual(code, 0) self.assertIn("sizeof(m) = 48\nsizeof(m[0]) = 16\nsizeof(m[0][0]) = 4\nm[1][2] = 7\n", output) def test_layout_is_row_by_row(self): output, _ = run("matrix_layout") cells = re.findall(r"m\[(\d)\]\[(\d)\] = +(\d+) está en (0x[0-9a-f]+)", output) self.assertEqual(len(cells), 12) self.assertEqual([int(c[2]) for c in cells], list(range(1, 13))) addresses = [int(c[3], 16) for c in cells] for row, column, _, _ in cells: position = int(row) * 4 + int(column) # la fórmula de los apuntes self.assertEqual(addresses[position] - addresses[0], position * 4) def test_grades_table(self): self.assertEqual(run("grades_table")[0].splitlines(), [ "Estudiante 0: suma 52, promedio 13.00", "Estudiante 1: suma 48, promedio 12.00", "Estudiante 2: suma 63, promedio 15.75", "Curso 0: suma 43, promedio 14.33", "Curso 1: suma 35, promedio 11.67", "Curso 2: suma 40, promedio 13.33", "Curso 3: suma 45, promedio 15.00", ]) def test_matrix_param_changes_only_the_rows_it_receives(self): lines = run("matrix_param")[0].splitlines() self.assertEqual(lines[3:5], ["Suma del curso 0: 43", "Suma del curso 0, solo 2 filas: 25"]) self.assertEqual(lines[5:], [" 15 10 18 13", " 12 17 9 14", " 18 10 15 20"]) def test_missing_columns_do_not_compile(self): messages, status, _ = build_source("errors/matrix_no_columns.c") self.assertNotEqual(status, 0) self.assertIn("must have bounds for all dimensions except the first", messages) def test_wrong_columns_are_noticed(self): messages, _, _ = build_source("errors/matrix_wrong_columns.c") self.assertIn("incompatible pointer type", messages) def test_const_matrix_is_only_seen_with_pedantic(self): messages, status, _ = build_source("errors/const_matrix.c") self.assertEqual((messages, status), ("", 0)) messages, status, _ = build_source("errors/const_matrix.c", "-Wpedantic") self.assertEqual(status, 0) self.assertIn("before C23", messages) def test_no_example_uses_const_matrix_parameters(self): for source in sorted(HERE.glob("*.c")) + sorted((HERE / "solution").glob("*.c")): with self.subTest(source=source.name): self.assertNotRegex(source.read_text(encoding="utf-8"), r"const\s+\w+\s+\w+\[\]\[") def test_comma_warns(self): messages, status, _ = build_source("errors/matrix_comma.c") self.assertEqual(status, 0) self.assertIn("left-hand operand of comma", messages) def test_column_out_of_bounds_seen_by_undefined_not_by_address(self): _, status, binary = build_source("errors/matrix_bounds.c", *SANITIZE) self.assertEqual(status, 0) self.assertEqual(execute([str(binary)], "2\n"), ("m[0][2] = 3\n", 0)) output, _ = execute([str(binary)], "3\n") self.assertIn("runtime error: index 3 out of bounds for type 'int [3]'", output) self.assertNotIn("AddressSanitizer", output) # Solo con address, nada avisa en este acceso. _, status, binary = build_source("errors/matrix_bounds.c", "-g", "-fsanitize=address") self.assertEqual(status, 0) output, _ = execute([str(binary)], "3\n") self.assertNotIn("AddressSanitizer", output) self.assertEqual(execute([str(binary)], "x\n"), ("Entrada inválida\n", 1)) def test_names(self): self.assertEqual(run("names"), ( "sizeof(names) = 48\n" "names[0] = Rosa, 4 bytes de texto\nnames[1] = Ana, 3 bytes de texto\n" "names[2] = Luis, 4 bytes de texto\nnames[3] = Zoila, 5 bytes de texto\n" "Primero: Ana\nnames[1] = Maria de lo\nPrimero: Luis\n", 0)) def test_matrix_add(self): self.assertEqual(run("matrix_add"), (" 11 22 33\n 44 55 66\n", 0)) def test_transposing_in_place_over_every_cell_changes_nothing(self): messages, status, binary = build_source("errors/transpose_in_place.c") self.assertEqual((messages, status), ("", 0)) self.assertEqual(execute([str(binary)]), ("1 2 3\n4 5 6\n7 8 9\n", 0)) if __name__ == "__main__": unittest.main()