Refactored configuration parsing to a separate file and added unit tests to it

1 files changed, 226 insertions, 0 deletions

diff --git a/config-parser.c b/config-parser.c
new file mode 100644
index 0000000..cd97dc7
--- /dev/null
+++ b/config-parser.c
@@ -0,0 +1,226 @@
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+
+#include "minitest.h"
+#include "config-parser.h"
+
+Result parse_config(int argc, char* argv[]) {
+	Result res;
+	res.success = false;
+	Config tmp;
+	tmp.precision = 0;
+	tmp.human_readable = false;
+
+	size_t i = 1;
+	char* argument;
+	char* precision = NULL;
+	while (i < argc) {
+		argument = argv[i];
+		int comp1 = strcmp(argument, "--precision") == 0;
+		if (
+			comp1 || strncmp(argument, "-p", 2) == 0
+		) {
+			if (precision != NULL) {
+				char* error_msg = malloc(44);
+				snprintf(
+					error_msg,
+					44,
+					"precision can't be specified multiple times"
+				);
+				res.result = error_msg;
+				return res;
+			}
+			i++;
+			if (strlen(argument) != 2 && !comp1) {
+				precision = argument + 2;
+				continue;
+			}
+			if (i == argc) {
+				char* error_msg = malloc(57);
+				snprintf(
+					error_msg,
+					57,
+					"`%s` should be followed by an integer argument",
+					argument
+				);
+				res.result = error_msg;
+				return res;
+			}
+			precision = argv[i];
+		} else if (
+			strcmp(argument, "--human-readable") == 0
+			|| strcmp(argument, "-h") == 0
+		) {
+			if (tmp.human_readable != false) {
+				char* error_msg = malloc(52);
+				snprintf(
+					error_msg,
+					52,
+					"human readability can't be specified multiple times"
+				);
+				res.result = error_msg;
+				return res;
+			}
+			tmp.human_readable = true;
+		} else {
+			size_t msg_size = 21 + strlen(argument);
+			char* error_msg = malloc(msg_size);
+			snprintf(
+				error_msg,
+				msg_size,
+				"unknown argument: `%s`",
+				argument
+			);
+			res.result = error_msg;
+			return res;
+		}
+
+		i++;
+	}
+
+	if (precision != NULL) {
+		char* endptr;
+		errno = 0;
+		tmp.precision = (int) strtol(precision, &endptr, 10);
+		if (errno != 0) {
+			char* error_msg = malloc(64);
+			char* errno_str = strerror(errno);
+			snprintf(
+				error_msg,
+				64,
+				"invalid precision: %s",
+				errno_str
+			);
+			free(errno_str);
+			res.result = error_msg;
+			return res;
+		}
+		if (*endptr != '\0') {
+			char* error_msg = malloc(53);
+			snprintf(
+				error_msg,
+				53,
+				"the precision may not contain non-numeric characters",
+				precision
+			);
+			res.result = error_msg;
+			return res;
+		}
+		if (tmp.precision <= 0) {
+			char* error_msg = malloc(50);
+			snprintf(
+				error_msg,
+				50,
+				"the precision can't be less than or equal to zero"
+			);
+			res.result = error_msg;
+			return res;
+		}
+	}
+
+	Config* conf = malloc(sizeof(int) + sizeof(bool));
+	conf->precision = tmp.precision;
+	conf->human_readable = tmp.human_readable;
+
+	res.success = true;
+	res.result = conf;
+	return res;
+}
+
+char* test_default_config() {
+	int argc = 1;
+	char* argv[] = { "stdu" };
+	Result res = parse_config(argc, argv);
+	Config* conf = (Config*) res.result;
+	mt_assert_eq(res.success, true);
+	mt_assert_eq(conf->precision, 0);
+	mt_assert_eq(conf->human_readable, false);
+	return 0;
+}
+
+char* test_precision_parsing() {
+	int argc;
+	Result res;
+	Config* conf;
+	char* error_msg;
+
+	argc = 3;
+	char* argv[] = { "stdu", "--precision", "3" };
+	res = parse_config(argc, argv);
+	conf = (Config*) res.result;
+	mt_assert_eq(res.success, true);
+	mt_assert_eq(conf->precision, 3);
+	mt_assert_eq(conf->human_readable, false);
+	free(conf);
+
+	argc = 2;
+	char* argv2[] = { "stdu", "-p" };
+	res = parse_config(argc, argv2);
+	mt_assert(
+		res.success == false,
+		"not specifying precision after `-p` didn't error"
+	);
+	free(error_msg);
+
+	argc = 4;
+	char* argv3[] = { "stdu", "--precision", "1", "-p3" };
+	res = parse_config(argc, argv3);
+	mt_assert(
+		res.success == false,
+		"specifying precision multiple times didn't error"
+	);
+	free(res.result);
+
+	return 0;
+
+}
+
+char* test_human_readability_parsing() {
+	int argc;
+	Result res;
+	Config* conf;
+	char* error_msg;
+
+	argc = 2;
+	char* argv[] = {
+		"stdu",
+		"--human-readable"
+	};
+	res = parse_config(argc, argv);
+	conf = (Config*) res.result;
+	mt_assert_eq(res.success, true);
+	mt_assert_eq(conf->precision, 0);
+	mt_assert_eq(conf->human_readable, true);
+	free(conf);
+
+	argc = 3;
+	char* argv3[] = {
+		"stdu",
+		"-h",
+		"-h"
+	};
+	res = parse_config(argc, argv3);
+	error_msg = (char*) res.result;
+	mt_assert_eq(res.success, false);
+	mt_assert(
+		strcmp(
+			error_msg,
+			"human readability can't be specified multiple times"
+		),
+		"should error on double argument of human readability"
+	);
+	free(error_msg);
+	
+	return 0;
+}
+
+void parsing_tests() {
+	mt_run_test(test_default_config);
+	mt_run_test(test_precision_parsing);
+	mt_run_test(test_human_readability_parsing);
+}