Mini-unit: #define + make
Learning goals
You will learn the following concepts/skills:
- unit testing – systematically test your code
- framework – create a simple framework for unit-testing future C code
- organization – learn how to organize a test suite
- test coverage – measure how thoroughly your tests exercise your code
- C preprocessor − how to use several of the most commonly used directives
- #define symbols – not just for defining constants
- #define macros – like functions but with special capabilities
#ifdef
/#ifndef
– disable sections of code with a#define
or GCC flag#include
guards – enable more versatile use of header (.h) files.
- Build systems – Create make files for compilation and testing.
- ANSI color codes – Print text in color on the terminal
Overview
Real-world software projects typically comprise tens, hundreds, or many thousands of files. Even in your ECE courses, your programming assignments will be getting bigger and more complex. Testing code by hand (i.e., by playing with it) is useless since there are so many components, and ways things can go wrong. can be complex—and slow.
Most serious software projects use two tools: a unit testing framework
(e.g., CUnit)
to organize and coordinate tests, and a build system
(e.g., make)
to manage the process of compiling, testing, and deploying the project. In this homework,
you will get a light introduction to both. In addition, you will learn to use console
logging effectively (as a complement to gdb), without littering your code with
printf(…)
statements.
You will create the following:
- Makefile – input file for the make build system. You will be able to build, test, submit, and/or pre-test your code with one command from bash or directly from Vim (and other editors).
-
miniunit.h – your own simple unit test library. You
can use this to test future assignments in this class, or for any other project you do
in C (or C++) beyond ECE 264. This consists of four
#define
macros that you can use in your test code. The most important macro you will create ismu_check(…)
, which is somewhat similar toassert(…)
. -
clog.h – your own library for smarter
printf
-style debugging and logging. From now on, instead of debugging withprintf(…)
directly, you will use function-like macros to print values in various formats and colors to make the output easier to view. You will use preprocessor directives to ensure that your debugging code does not interfere with your tests, or show up inadvertently when others are testing your code.
Starter code
You will create your Makefile, clog.h, and miniunit.h from scratch (i.e., i.e., starting with a blank file).
We are providing a simple program for counting words that you can use to test your HW05. You will be modifying this program to use miniunit.h and clog.h. There is also a script called print256colors.sh (created by Tom Hale). It will not be used directly for the assignment, but running this script will give you some exposure to the range of colors your terminal can display.
Run 264get hw05
to
fetch these files.
Part 1: Makefile
Create a file called Makefile that will be used as input too the make command. This file will have instructions for how to not only compile a program, but also run your tests, submit, run the pretester, and even run a code coverage tester to search for areas of your code that your tests may not be covering.
The Makefile must be specific to a particular project. For HW05, you will create a Makefile for the count_words project that is included in the starter. On future assignments, you can easily change a few variables at the top of your Makefile to make it work for future assignments.
Structure of a Makefile
A Makefile is a text file named “Makefile” (exactly). It may contain variables, rules, and phony targets.
# VARIABLES LHS=RHS LHS=RHS … # RULES target: prerequisites… action action … # .PHONY TARGET - declare targets that do not correspond directly to an output file .PHONY: target_name target_name …
Variables. The variables section (at the top) contains filenames, and other information that you will use in the commands that build and manage your project. In this homework, we have specified exactly what variables you need in the Requirements table.
Rules. A rule consists of a target, ≥0 prerequisites, and ≥0 actions. Normally, most rules in make files describe how to compile (or generate) a particular file. We will also use so-called phony targets, which are essentially just scripts for performing actions related to your project (e.g., submit, run tests, etc.).
Targets. The target of a rule is usually a file that will be created by the actions in that rule. For example, the test_count_words rule will create the test_count_words executable file. For phony targets, the target is the name of the command.
Prerequisites. The prerequisites of a rule are the targets that it The prerequisites… are a list of targets upon which that rule depends. For example, test_count_words depends on count_words.c, count_words.h. If you were to use your new console log macros in your count_words.c, then clog.h would also be a prerequisite of test_count_words.
Actions. The actions in each rule consist of commands that could be entered in your shell (bash). Your bash aliases will not work here. That means simply typing gcc would not include the flags we require for the class. Therefore, you will create some variables to make sure you get those flags. (These are given in the Requirements table below.)
⚠Actions must be indented with a tab character, not four spaces. If you are using Vim with the .vimrc we provided, this is taken care of for you.
Phony targets. At the end of your Makefile you should have a rule called .PHONY. The prerequisites of .PHONY should be every target that is not a real file target.
Running make.
From bash, type make target
to
build that target. For example, typing make test_count_words
would compile the
count_words project to create or update the executable file test_count_words. If the rule
has any prerequisites—e.g., files must be up-to-date or commands to be run before creating
test_count_words—those are built first.
The first rule in the Makefile will be the default. When you run
make
from bash (with no arguments), it builds the default
target. Calling make target
builds the specified target.
The specifics on what your Makefile must contain are in the requirements table. These slides from Zhiliang Xu have a good explanation of makefiles.
Instructions
You may hand-copy snippets from HW05, but do not copy-paste. You won't learn as well, and it won't work anyway.)
- Create a very simple Makefile to just compile test_count_words
- Create a blank file called Makefile.
- Add one rule to compile test_count_words as follows.
test_count_words: count_words.c count_words.h gcc -o test_count_words count_words.c test_count_words.c -g -std=c11 -Wall -Wshadow -Wvla -Werror -pedantic -Wno-unused-function
- Test the Makefile from bash.
- From bash:
you@ecegrid-thin1 ~/hw05 $
make
- From Vim:
:make
- From bash:
- Modify your Makefile to use variables where possible.
- Add the CC and CFLAGS variables at the top. (See the Requirements table.) Here's a start:
EXECUTABLE=test count words SRC C=count words.c TEST C=test count words.c SRC H=count words.h CC=gcc CFLAGS=-g -std=c11 -Wall -Wshadow -Wvla -Werror -pedantic -Wno-unused-function SHELL=/bin/bash ASG NICKNAME=HW55⚠ CFLAGS should not include-DDEBUG
or-DNDEBUG
. - Modify your rule to use the variables.
$(EXECUTABLE): $(SRC C) $(TEST C) $(SRC H) $(CC) -o test count words count words.c test count words.c $(CFLAGS)
- Test the Makefile in the same manner as before.
- Add the CC and CFLAGS variables at the top. (See the Requirements table.) Here's a start:
- Add a phony rule to submit your code
- Add a rule called
submit
that submits the assignment. Use the variables you defined. You can add more if needed. Yoursubmit
rule does not need any prerequisites. - Add the following line to the bottom of your Makefile:
.PHONY: submit
- Type
make submit
in bash or:make submit
in Vim to test your rule for the submit phony target. . You may submit to it to test your Makefile, but will not be scored and will not affect your grade.
- Add a rule called
-
Add a phony rule to run your tests.
- Add a rule called
test
. Hand-copy the following code. We will be adding a bit more to this rule later in HW05. - Add
test
to your .PHONY rule. - Type
make test
in bash or:make test
in Vim to test your rule for the test phony target.
test: debug $(TEST_EXPECTED) @# If actual output matches expected output then count it as a success @if diff -a -B <("./$(EXECUTABLE)") $(TEST EXPECTED) &> /dev/null ; then \ echo "Test passed: output of $(EXECUTABLE) matches $(TEST_EXPECTED)" ; \ else \ echo "Test failed: output of $(EXECUTABLE) does NOT match $(TEST_EXPECTED)" ; \ fi - Add a rule called
-
Add a rule to run the pretester.
- Add a rule called
pretest
that runs the pretester. It should call your submit rule first (using a prerequisite) and then call264test
. Use the variables you created (includingASG_NICKNAME
) in the actions for this rule. ⚠ Do not enter “HW55”, “count_words.c”, “test_count_words.c”, or “expected.txt” directly. - Add
pretest
to your .PHONY rule. - Type
make pretest
in bash or:make pretest
in Vim to test your rule for the pretest phony target. It is a dummy pretester that gives everyone 100%.
- Add a rule called
- Add a rule called
clean
that deletes the executable file (test_count_words). The command to delete a file(s) isrm files…
. When working at the terminal, we have that command set to prompt for confirmation. To ensure thatmake
does not prompt for confirmation, you add the-f
flag. Thus, the whole command will berm -f files…
.make clean
should delete the executables (test_count_words and any data files created by the code coverage check (if any). To delete file(s), userm -f ▒▒▒
. The-f
tells the rm command not to prompt for confirmation or print an error if no such file exists.⚠ Be careful not to delete your .c or .h files, or your Makefile. - Add the remaining rules, as specified in the Requirements table. Some additional
hints are below. Be sure all rules except for
$(EXECUTABLE)
are listed in your.PHONY:
line.
Part 2. Test coverage checking
Code coverage testing—including statement coverage—can help you find bugs in your code by discovering aspects of the functionality that your tests are not exercising. In this section, you will learn how to use test coverage checking, and integrate that functionality into your Makefile.
We will be using one kind of coverage, called line coverage. It runs your tests and monitors which statements in your implementation code were executed. If any statements were not executed, it typically indicates that either your tests are not exercising all of the functionality. It is also possible that you have some dead code. Either way, it should be rectified.
We will be using a tool called GCOV, which works in conjunction with GCC. To check test coverage using GCOV, use this:
# Compile a special version of executable with coverage checking gcc -o executable source files... -ftest-coverage -fprofile-arcs -DNDEBUG # Run the executable to record coverage statistics ./executable # Print a coverage summary gcov -f count_words.c
Detailed information, such as which lines were executed, can be found by opening the count_words.c.gcov in your editor.
Instructions
- Try running GCOV from bash. Later, you will be adding this to your Makefile but
it is important to first make sure it works for you, and make sure you understand what
it does.
You could do this with the included count_words program, but to show this in context of something more familiar, we will demonstrate using and implementation of HW04.
you@ecegrid-thin1 ~/HW05 $
gcc -o test_mintf mintf.c test_mintf.c -fprofile-arcs -ftest-coverage -DNDEBUG
you@ecegrid-thin1 ~/HW05 $
./test_mintf
▒▒▒▒▒▒▒▒▒▒ ▒▒▒▒▒▒▒▒▒▒you@ecegrid-thin1 ~/HW05 $
gcov -f mintf.c
Function 'mintf' Lines executed:61.29% of 31 Function 'print_integer' Lines executed:75.00% of 8 Function '_print_integer_digit' Lines executed:81.82% of 11 File 'mintf.c' Lines executed:68.00% of 50 Creating 'mintf.c.gcov'The example above is what you would see if you have not tested adequately. In this case, only 68% of the lines in count_words.c were executed at all. None of the three functions was tested thoroughly. Hopefully, the stats for your code will report 100% coverage.This metric excludes blank lines, comments, and lines containing only braces, so 100% line coverage should be attainable. - Add a rule called
coverage
to your Makefile to check code coverage. Use the variables you defined (e.g., CC, CFLAGS, etc.) wherever possible. Hint: It should have two .c files as prerequisites, and three actions. Don't forget to addcoverage
to the list of phony targets (i.e.,.PHONY submit test ▒▒▒▒▒▒▒▒▒▒▒▒▒
). - Type
make coverage
in bash or:make coverage
in Vim to test your rule for the coverage phony target. Verify that it created five new files: count_words.c.gcov, count_words.gcda, count_words.gcno, test_count_words.gcda, test_count_words.gcno. - Modify the
clean
rule in your Makefile to remove the data files created by GCOV. You should use wildcards (*.c.gcov *.gcda *.gcno
). - Type
make clean
in bash or:make clean
in Vim to test your rule for the clean phony target. Verify that the five files created by GCOV (count_words.c.gcov, count_words.gcda, count_words.gcno, test_count_words.gcda, test_count_words.gcno) were deleted.
Part 3: clog.h
For this part, you will create a reusable library for debugging any C project. In the process, you will learn about the C preprocessor and ANSI control codes.
Instructions
In a new file called clog.h, create each of the log_▒▒▒(…)
macros specified in the Requirements table. We recommend writing them in the order shown
(e.g., log_msg(…)
first, then
log_int(…)
, and so on).
To test, make a separate test file called test_clog.c with calls to each of the macros.
Use #ifdef DEBUG
(and #endif
) to ensure that your
log_▒▒▒(…)
macros only work when the program
was compiled with gcc -DDEBUG ▒▒▒
. Without
gcc -DDEBUG
, your program should still compile, but they should
have no effect. That can be done by adding an empty macro.
Here is a skeleton as a starting point. You are welcome (and encouraged) to modify this, as you see fit.
#ifdef DEBUG
#define log_msg(msg) fprintf(stderr, "%s", (msg)) // enabled
#else
#define log_msg(msg) // disabled
#endif
For readability, you may wish to indent like this (below). The #
must
be the first character on the line. Indenting macros like this is not required by
the code quality standards. Use whichever you prefer.
#ifdef DEBUG
# define log_msg(msg) fprintf(stderr, "%s", (msg)) // enabled
#else
# define log_msg(msg) // disabled
#endif
Wrap your entire clog.h in an include guard like this:
#ifndef __CLOG_H__ #define __CLOG_H__ ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ #endif
See the article linked above for details on include guards.
Part 4. Modify Makefile to report success/failure in color
This will be a small change. You will use the same ANSI color codes that you used for clog.h. The success message should be printed in green. The failure message should be printed in red.
- Test printing in color from bash, to make sure it works for you.
- Type
echo -e '\x1b[31mTOMATO\x1b[0m'
to print “TOMATO” in red. - Type
echo -e '\x1b[32mCELERY\x1b[0m'
to print “CELERY” in green.
- Type
-
Modify your
test
rule to use the ANSI color code in a similar manner.- Change the
echo
statements in yourtest
rule to useecho -e
instead of justecho
. - Modify the messages so they print the color code before the message—green for success, or red for failure—and then print the reset code after the message.
- Change the
- Test.
- Type
make test
in bash or:make test
in Vim to test your rule for the test phony target.
- Type
Part 5. Use clog.h in test_count_words.c, and Makefile
- In test_count_words.c, modify the
printf(…)
statements to uselog_int(…)
instead. - In Makefile, add clog.h to the SRC_H
variable. It should now be
SRC_H=count_words.h clog.h
- Test.
Part 6. miniunit.h
Until now, we have used a very low-tech method of structuring our tests
with the expected.txt and the diff
command. That method
is based on the more general principle of unit testing.
In unit testing, programmers write collections of small functions that test
some aspect of a program. For example, in mintf(…)
in
HW04,
you might have a unit test for small positive integers in base 10, another unit
for small negative numbers, one for extreme bases, extreme positive values,
extreme negative values, and so on. Each test is its own function.
As the number and complexity of tests grows, it becomes necessary to have
a foundation of code for running and organizing them. This is called a
unit test framework. There are
unit test frameworks for every major programming language.
For C, one example is
CUnit.
These typically have special-purpose macros for checking assumptions, similarly
to the assert(…)
macro, which we have already
covered this semester, but with a unit test framework, we may allow the code
to continue, even if an assumption is not met, since the goal is simply to check.
In addition to the checking macros, real-world testing frameworks have mechanisms
for setting up the needed environment that the program-in-test
depends on (e.g., files, network connections, etc.), and sophisticated interfaces
for visualizing the results and scheduling test runs.
In this homework, you will create a very simple unit test framework… let's call it
a unit test library. You may use this to test future assignments. We will illustrate
by example.
Using miniunit.h to test — minimal example
Suppose you have the following (very trivial) module for doing arithmetic calculations involving the number 3.
three.c 1 #include "three.h" 2 3 int times_3(int n) { 4 return n * 3; 5 } 6 7 int divided_by_3(int n) { 8 return n % 3; // BUG 9 } 10 11 int plus_3(int n) { 12 return n * 3; // BUG 13 } 14 15 int minus_3(int n) { 16 return n - 3; 17 }
three.h 1 int times_3(int n); 2 int divided_by_3(int n); 3 int plus_3(int n); 4 int minus_3(int n);
Here is the general format for every unit test function (e.g., in test_three.c). You will typically have several of these in your test_▒▒▒.c.
int test_▒▒▒() { mu_start(); // set up the test // … mu_check(condition); // … mu_check(condition); // … mu_end(); // finish the test }
Then, to call all of your unit test functions, you will have a runner
function (e.g., main(…)
) like this:
int main(int argc, char* argv[]) { mu_run(test_▒▒▒); mu_run(test_▒▒▒); mu_run(test_▒▒▒); mu_run(test_▒▒▒); return EXIT_SUCCESS; }
Using the above format, we create the following unit test suite (group of tests) for our three-arithmetic module.
// test_three.c
#include <stdio.h>
#include <stdlib.h>
#include "miniunit.h"
#include "three.h"
int test_plus_3() {
mu_start();
mu_check(plus_3(1) == 4); // will FAIL
mu_end();
}
int test_minus_3() {
mu_start();
mu_check(minus_3(1) == -2);
mu_end();
}
int test_times_3() {
mu_start();
mu_check(times_3(1) == 3);
mu_end();
}
int test_divided_by_3() {
mu_start();
mu_check(divided_by_3(1) == 0); // will FAIL
mu_end();
}
int main(int argc, char* argv[]) {
mu_run(test_plus_3); // will FAIL
mu_run(test_minus_3);
mu_run(test_times_3);
mu_run(test_divided_by_3); // will FAIL
return EXIT_SUCCESS;
}
Your unit test library, using #define
macros will convert that seemingly
simple test code into a colored summary, including the name of the test function
and the line where it failed. Here is the expected out put for the test above:
$ gcc -o test_three three.c test_three.c $ ./test_three Test failed (test_plus_3) at line 8 Test passed (test_minus_3) Test passed (test_times_3) Test failed (test_divided_by_3) at line 26 $
Instructions
Create the four #define
macros as specified in the Requirements table.
⚠ Success and failure messages should be printed by
mu_run(…)
(not mu_check(…)
),
and should not rely on log_green(…)
and
log_red(…)
.
Those will be disabled when DEBUG
is not defined (i.e., when
-DDEBUG
was not passed to the compiler); miniunit.h
is expected to work either way.
Update Makefile
SRC_H=count_words.h clog.h miniunit.h
Part 7. Use miniunit.h to improve test_count_words.c
This part will teach you how to use miniunit.h in practice for future assignments. We are giving you the code for free, so it shouldn't take more than about 15 minutes to type and test.
- At the top of test_count_words.c, include miniunit.h.
(You can also remove the
#include "clog.h"
since your miniunit.h will include that.) - Add three test functions above
main(…)
:int _test_empty()
,int _test_simple()
, andint _test_hard()
. - Inside each test function, add
mu_start()
at the beginning, andmu_end(…)
just before the end. - Add at least one call to
mu_check(…)
in betweenmu_start(…)
andmu_end(…)
. - At the top of
main(…)
, addmu_run(_test_empty)
,mu_run(_test_simple)
, andmu_run(_test_hard)
. - The result may look something like this:
#include <stdio.h> #include <stdlib.h> #include "count_words.h" #include "miniunit.h" int _test_empty() { mu_start(); //------------------------------- mu_check(count_words("") == 0); //------------------------------- mu_end(); } int _test_simple() { mu_start(); //------------------------------- mu_check(count_words("apple") == 1); mu_check(count_words("boring boxes") == 2); mu_check(count_words("apple banana") == 2); mu_check(count_words("apple banana cherry") == 3); //------------------------------- mu_end(); } int _test_hard() { mu_start(); //------------------------------- mu_check(count_words("famigerate fiddle-faddle") == 2); mu_check(count_words("Mary's mongoose") == 2); mu_check(count_words("plumbers' platitudes") == 2); //------------------------------- mu_end(); } int main(int argc, char* argv[]) { mu_run(_test_empty); mu_run(_test_simple); mu_run(_test_hard); log_int(count_words("My apples are sweet.")); log_int(count_words("My friend's apples are sweeter.")); log_int(count_words("A pear is sweeter than an apple..")); return EXIT_SUCCESS; }
Note: Due to the intentially planted bugs in count_words.c,_test_simple(…)
will fail on "apple banana" (due to 'a'), and_test_hard(…)
will fail on "familgerate fiddle-faddle" (due to '-'). - Run the tests from bash using
make test
.you@ecegrid-thin1 ~/HW05 $
make test
gcc -std=c11 -g -Wall -Wshadow --pedantic -Wvla -Werror count_words.c test_count_words.c -o test_count_words -DDEBUG Test passed (_test_empty) Test failed (_test_simple) at line 20 Test failed (_test_hard) at line 29 count_words("My apples are sweet.") == 4 count_words("My friend's apples are sweeter.") == 6 count_words("A pear is sweeter than an apple..") == 8 Test failed: output of {{ test_exe }} does NOT match {{ test_txt }}Reminder:count_words(…)
has intentionally planted bugs. It is okay that some of the results are obviously incorrect and the tests fail. The purpose of tests is to detect flaws. If the flaws are detected, then the test worked correctly.We are giving you this code for free. You are welcome to make changes, or hand-copy as is, as long as you understand what it is doing. If not, please ask. - Try running all of the rules in your Makefile with your new test code.
- You must submit your test_count_words.c, even if it is identical to the code above.
Requirements
- Your submission must contain each of the following files, as specified:
file contents miniunit.h macros mu start()
- Declare a local variable and initialize it to 0.
- The purpose of this variable is to store the line
number of the first "check".
- By “check” we mean a call to
mu_check(…)
in the test code that uses miniunit.h.
- By “check” we mean a call to
- ⚠ Name of variable must begin with
__mu_
(e.g., __mu_line_number_of_first_failure). - Initial value of this variable should be 0.
- Hint:
mu_start(…)
will be only one line; there should be no semicolon.
mu check(condition)
- If condition is false, store the line number of this
mu_check(…)
call in the variable that you created inmu_start(…)
—but only for the first call tomu_check(…)
with a condition that is false.- Store the line number only on the first check that fails.
- If you have multiple calls to
mu_check(…)
that fail, you want to keep only the line number of the first one that failed.
- You can get the current line number with
__LINE__
.
mu run(function)
- Call
function()
(with no parameters). - If it returns 0, then print (in green on stderr):
Test passed: function - If it returns a line number (≥1), then print (in red on stderr):
Test failed: function at line line# - ⚠ This should work even when the program is not compiled with
-DDEBUG
.- This may require minor changes to your clog.h to ensure that
mu_run(…)
works with or without-DDEBUG
, but thelog_▒▒▒(…)
macros only work when compiled with-DDEBUG
. - Hint: This means
mu_run(…)
should not calllog_green(…)
orlog_red(…)
directly. This is a big hint! The snippet given in Q12 should help with this.
- This may require minor changes to your clog.h to ensure that
mu end()
mu_check(…)
) that failed, or 0 if all checks succeeded.- Hint: This will be just one line; there should be no semicolon.
clog.h constants ANSI color codes- 7 codes: red, green, yellow, blue, magenta, cyan, and reset
- The first (ANSI_RED) is provided below.
- Search for the rest of the codes online. This is so you can see that these are standard, and not part of ECE 264. As long your source agrees with our ANSI_RED below, the rest should be fine.
#define ANSI_RED "\x1b[31m" // ← OK to copy
#define ANSI_GREEN "▒▒▒▒▒▒▒▒"
#define ANSI_YELLOW "▒▒▒▒▒▒▒▒"
#define ANSI_BLUE "▒▒▒▒▒▒▒▒"
#define ANSI_MAGENTA "▒▒▒▒▒▒▒▒"
#define ANSI_CYAN "▒▒▒▒▒▒▒▒"
#define ANSI_RESET "▒▒▒▒▒▒▒▒"
macros log msg(msg)
- ⇒
fprintf(stderr, "%s", msg)
log int(n)
- Calling
log_int(3+3)
should print this:3+3 == 6
-
Here's a naïve way to do it:
#define log_int(n) fprintf(stderr, "%s == %d\n", (#n), (n))
You may copy/adapt that, but you will need a way to selectively enable this (and otherlog_▒▒▒(…)
) macros only when the symbol DEBUG is defined.
log str(s)
-
log_str(s)
⇔fprintf(stderr, "s == %s\n", s)
- Calling
char* s = "abc";
and thenlog_str(s)
should print this:s == "abc"
- Calling
log_str("xyx")
should print this:"xyx" == "xyx"
log char(c)
-
log_char(ch)
⇔fprintf(stderr, "ch == '%c'\n", ch)
log addr(addr)
-
log_addr(addr)
⇔fprintf(stderr, "addr == %p\n", addr)
- Examples:
int n = 5; log_addr(&n)
// should print something like&n == 0x7fff938d
int* a_n = &n; log_addr(a_n)
// should print something likea_n == 0x7fff938d
- Note: You need a cast when passing an address to
printf("… %p …")
log red(format, ...)
-
Equivalent to
fprintf(stderr, format, ...)
except text is printed in red. - To do this, print ANSI_RED, then call
fprintf(…)
, and finally print ANSI_RESET. - ⚠The specification for this macro above is not code. For your actual
#define
you will need something likelog_red(...)
. In the RHS, use__VA_ARGS__
. Search the web for “variadic macros” for more information on this.
log green(format, ...)
- Like
log_red(…)
but in green - See the warning in
log_red(…)
.
log yellow(format, ...)
- Like
log_red(…)
but in yellow - See the warning in
log_red(…)
.
log blue(format, ...)
- Like
log_red(…)
but in blue - See the warning in
log_red(…)
.
log magenta(format, ...)
- Like
log_red(…)
but in magenta - See the warning in
log_red(…)
.
log cyan(format, ...)
- Like
log_red(…)
but in cyan - See the warning in
log_red(…)
.
Makefile makefile Variable definitions (top section)name value (exactly) SRC_C count_words.c SRC_H count_words.h clog.h miniunit.h TEST_C test_count_words.c TEST_EXPECTED expected.txt TEST_ACTUAL actual.txt EXECUTABLE test_count_words ASG_NICKNAME HW55 CC gcc CFLAGS -g -std=c11 -Wall -Wshadow -Wvla -Werror -pedantic -Wno-unused-function CFLAGS_GCOV $(CFLAGS) -fprofile-arcs -ftest-coverage SHELL /bin/bash Rulestarget name action(s) $(EXECUTABLE) Compile the executable. - Reminder: Use variables in all rules, wherever possible.
test Run executable (test_count_words).If output matches expected.txt), print…
Test passed: output of test_count_words matches expected.txtIf output does not match expected.txt, print…
Test failed: output of test_count_words does NOT match expected.txtsubmit Submit the assignment using 264submit. - Rule will look like this:
submit: ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ 264submit ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒
- Reminder: Use variables. There should be no raw filenames in this rule.
pretest Pretest the assignment using 264test. - Rule should submit before pretesting.
- Simply make submit a prerequisite of pretest (i.e.,
pretest: submit
) - This rule is simple, so we'll give it to you:
pretest: submit 264test $(ASG_NICKNAME)
coverage Check the code coverage of your tests.
debug Compile test_count_words with DEBUG defined. - Hint: This rule will be exactly the same as $(EXECUTABLE),
except the name is
debug
and you will add a GCC flag to the end to set the DEBUG symbol.
clean Delete all files created by any of the above rules. - Use the variables wherever possible to avoid duplicating information.
- Information in the variables (above) should not be duplicated elsewhere. ◀◀◀◀◀◀
- Use prerequisites to reduce duplication and ensure each action has what it needs.
- A rule should depend (directly or indirectly) on every file it uses.
- Do not repeat exactly the same compilation command in multiple places.
- Ex: test should depend on debug.
- Do not add pointless (unnecessary) prerequisites.
- Ex: Any rule that depends on test_count_words should not list count_words.c or test_count_words.c as prerequisites since they are implied by test_count_words and thus unnecessary.
- Ex:
make clean
should not depend on anything.
- Do not define DEBUG or NDEBUG in your compilation
commands unless otherwise specified in these requirements.
make debug
: Compile with DEBUG.make coverage
: Compile with NDEBUG but not DEBUG to reduce the effect of logging macros (e.g.,log_int(…)
, etc.) and assertions (e.g.,assert(…)
) on the metrics.
- miniunit.h should use clog.h to the extent possible—at least use the ANSI_▒▒▒ constants.
make submit
should result in:
264submit HW55 count_words.c test_count_words.c expected.txt miniunit.h clog.h
- You may hand-copy any code snippets you find in this homework
description into your HW05 submission.
- ⚠ Do not use copy-paste. You learn more from hand-copying unfamiliar syntax. Expect problems if you ignore this.
- Adaptation is strongly recommended. Some snippets may not work in your file as is.
- Be sure you understand what you are copying. Correct functioning of your code is your responsibility.
- Copying from this page is not necessary. This permission is given as a convenience, since some of the syntax may be unfamiliar, and this homework is more tightly specified than most others.
- Names of helper macros (if any) must begin with “
__mu_
”. - Do not repeat the ANSI codes anywhere other than in clog.h and Makefile.
- Required macros in clog.h
(i.e.,
log_▒▒▒(…)
) should work ONLY when the symbol DEBUG is defined (i.e., when you compile withgcc -DDEBUG
).- Hint: You will need to use some combination of
#ifdef
,#ifndef
,#else
, and#define
- If you use any helper macros (e.g.,
__mu_log_color(…)
), they may work even when DEBUG is not defined.
- Hint: You will need to use some combination of
- ⚠ Macros in miniunit.h should work regardless of the symbols defined (e.g., DEBUG).
- ⚠ Do not print ANSI codes when output is being directed to a file or other application.
- This applies to all parts of this homework, including test_count_words.c, Makefile, clog.h, and miniunit.h.
- In C, you can use
isatty(STDERR_FILENO)
to determine if the output is going to a real terminal ("TTY"), versus being redirected to a file or something else.
-
You may use any of the following:
header functions/symbols allowed in… stdbool.h bool
,true
,false
*.c
,*.h
stdio.h fputs
,fprintf
,stderr
*.c
,*.h
string.h strcmp
test_count_words.c
unistd.h isatty
,STDERR_FILENO
*.c
,*.h
stdlib.h EXIT_SUCCESS
test_count_words.c
printf(…)
at all, since all output is going tostderr
. - Code that includes clog.h and/or miniunit.h and uses macros from them must compile and run whether or not DEBUG was defined.
- miniunit.h should have
#include "clog.h"
so that users of miniunit.h don't need to include both. -
Submissions must meet the code quality standards
and the course policies on homework and academic integrity.
-
⚠ That means everything must compile successfully, even when compiled
with the usual compiler flags
(
gcc -g -std=c11 -Wall -Wshadow -Wvla -Werror -pedantic -DNDEBUG -Wno-unused-function
)—and without-DDEBUG
. Furthermore, tests using your miniunit.h should work properly with or without-DDEBUG
.
-
⚠ That means everything must compile successfully, even when compiled
with the usual compiler flags
(
Submit
To submit HW05 from within your hw05 directory,
type
264submit HW05 miniunit.h clog.h Makefile test_count_words.c
Pre-tester ●
The pre-tester for HW05 has not yet been released. As soon as it is ready, this note will be changed.
Q&A
-
Shouldn't a Makefile refer to .o files?
We are using makefiles in a simplified manner that does not require awareness of .o files. -
How do I print a double quotation mark using
printf(…)
?
printf("\"")
-
How do I use a variadic macro to pass arguments from
log_red(…)
tofprintf(…)
?
In the LHS of the #define, use “...
” to indicate 1 or more arguments. In the RHS, use __VA_ARGS__ to pass those same arguments to the next function (e.g.,fprintf(…)
). Note that “...
” stands for one or more, not zero or more.Here's a simple example:
#define printf_to_stderr(...) fprintf(stderr, __VA_ARGS__)
That macro would convertprintf_to_stderr("%d", 3)
tofprintf(stderr, "%d", 3)
. -
Should I have a semicolon at the end of the RHS of a
#define
macro?
No. The person using the macro will normally include the semicolon. -
How can I continue the RHS of a
#define
macro definition onto the next line?
Put a backslash ("\") at the end of the line.#define profess_love_for_food(food) printf("I love %s", \ food)
-
Can I have a macro with multiple C statements?
Yes. In theory, you could just have the two statements separated by a semicolon like this:// BAD #define profess_love_for_two_foods(food1, food2) \ printf("I love %s", food1); \ printf("I love %s", food2)
However, that would lead to surprising results if someone who doesn't follow the code quality standards calls that macro in an if statement like this:if(1 == 0) profess_love_for_two_foods("soap", "poison");
Only the first statment would be connected to theif
statement.if(1 == 0) printf("I love %s", "soap"); printf("I love %s", "poison");
It is tempting to just put curly braces around the two statements, but that also causes problems.// BAD #define profess_love_for_two_foods(food1, food2) { \ printf("I love %s", food1); \ printf("I love %s", food2); \ }
The problem comes back to uncivilized oafs who write
if
statements without curly braces, like this:if(age >= 30) profess_love_for_two_foods("chocolate", "pizza"); else profess_love_for_two_foods("spinach", "broccoli");
The above example would result in this:
if(age >= 30) { printf("I love %s", "chocolate"); printf("I love %s", "pizza"); }; ← PROBLEM else { printf("I love %s", "spinach"); printf("I love %s", "broccoli"); };
The standard solution is to wrap the statements in ado { … } while(false)
block. Because thedo…while
requires a semicolon, this actually works out like we want.Yes, it is ugly. Hacks like this are not something the instructor would normally condone, but it is standard practice because there are very few truly versatile options for this.// USE THIS WAY #define profess_love_for_two_foods(food1, food2) do { \ printf("I love %s", food1); \ printf("I love %s", food2); \ } while(false)
-
What is HW55? Is that a typo?
HW55 is a dummy assignment that you will use to test the rules in your Makefile that deal with assignment submission and pretesting. It will not be scored and will not affect your grade.HW05 is the “real” assignment you are doing here. -
Why does miniunit.h need
mu_start(…)
andmu_end(…)
?
These give a relatively clean and consistent form to your unit tests, so you can focus on the code that matters for each particular test.Withoutmu_start(…)
andmu_end(…)
, one might resort to a naïve approach, like this:YUK!int test_count_words_▒▒▒▒▒() { int test__mu_failure_line_num = __MU_SUCCESS; mu_check(▒▒▒▒▒▒▒▒▒▒); mu_check(▒▒▒▒▒▒▒▒▒▒); mu_check(▒▒▒▒▒▒▒▒▒▒); return __mu_failure_line_num; }The programmer should not have to know the specific internal names used by miniunit.h! If they get it wrong, then it won't work properly withmu_check(…)
.Of course, they could avoid the problem of consistency if they do the whole thing without any macros—i.e., without miniunit.h—but then the above skeleton would be even messier!YUK! YUK! YUK! YUK! YUK!int test_count_words_▒▒▒▒▒() { const int __MU_SUCCESS = 0; int __mu_failure_line_num = __MU_SUCCESS; if(!(▒▒▒▒▒▒▒▒▒▒) && __mu_failure_line_num == __MU_SUCCESS) { __mu_failure_line_num = __LINE__; } if(!(▒▒▒▒▒▒▒▒▒▒) && __mu_failure_line_num == __MU_SUCCESS) { __mu_failure_line_num = __LINE__; } if(!(▒▒▒▒▒▒▒▒▒▒) && __mu_failure_line_num == __MU_SUCCESS) { __mu_failure_line_num = __LINE__; } return __mu_failure_line_num; }Withmu_start(…)
andmu_end(…)
—and adding a divider comment (optional)—you get this:GOODint test_count_words_▒▒▒▒▒() { mu_start(); //──────────────────────────────────────── mu_check(▒▒▒▒▒▒▒▒▒▒); mu_check(▒▒▒▒▒▒▒▒▒▒); mu_check(▒▒▒▒▒▒▒▒▒▒); //──────────────────────────────────────── mu_end(); }mu_start(…)
andmu_end(…)
also make your unit testing library more extensible. If you wanted to change how your tests are organized and/or reported, you could do so without changing all of your test code that uses it. -
How do I convert the
printf(…)
statements in test_count_words.c to uselog_int(…)
?
Here is an unrelated example that prints the output of a function usingprintf(…)
.#include <stdio.h> #include <stdlib.h> int triple(int n) { return n * 3; } int main(int argc, char* argv[]) { // BAD (… or less good) printf("triple(5) == %d\n", triple(5)); printf("triple(4) == %d\n", triple(4)); printf("triple(3) == %d\n", triple(3)); printf("triple(2) == %d\n", triple(2)); printf("triple(1) == %d\n", triple(1)); return EXIT_SUCCESS; }
Here is the same example converted to uselog_int(…)
.#include <stdio.h> #include <stdlib.h> #include "clog.h" int triple(int n) { return n * 3; } int main(int argc, char* argv[]) { // GOOD log_int(triple(5)); log_int(triple(4)); log_int(triple(3)); log_int(triple(2)); log_int(triple(1)); // Advantages over raw printf(…) // ∙ Easy to "turn off" when it is time to submit your code. // ∙ Less duplication means fewer oppportunities for bugs. return EXIT_SUCCESS; }
Withlog_int(…)
, you can print the expression itself, along with its value. -
What does
#x
do in a#define
macro?
It expands to the text of the expression, instead of its value. This is easiest to see if you test using the /usr/bin/cpp command.Here is an example, which uses thelog_int(…)
snippet given in the Requirements table.// demonstrate_hash.c #include <stdio.h> #include <stdlib.h> #define log_int(n) fprintf(stderr, "%s == %d\n", (#n), (n)) int main(int argc, char* argv[]) { log_int(3 + 3); return EXIT_SUCCESS; }
If we process that with the preprocessor directly (instead of via gcc), we can see what it becomes.you@ecegrid-thin1 ~/HW05 $
/usr/bin/cpp demonstrate_hash.c
… int main(int argc, char* argv[]) { fprintf(stderr, "%s == %d\n", ("3 + 3"), (3 + 3)); return 0; }Notice that the third argument tofprintf(…)
is a string literal,"3 + 3"
—the text of the argument that was passed tolog_int(…)
. That is different from the fourth argument, which is the value of that parameter,3 + 3
(= 6). -
How do I test my clog.h?
Here's an example. As with all other code snippets in this homework description (for HW05 only), you may hand-copy or adapt this. You may also test in some other way of your choice.// test_clog.c #include "clog.h" int main(int argc, char* argv[]) { log_msg("COLORS\n"); log_green("green\n"); log_red("red\n"); log_yellow("yellow\n"); log_blue("blue\n"); log_magenta("magenta\n"); log_cyan("cyan\n"); log_msg("\n"); log_msg("SHOPPING LIST\n"); log_green("bok choy x %d bunches\n", 3); log_red("tomatos x %d\n", 5); log_yellow("lemon x %d\n", 3); log_blue("borage x %d flowers\n", 100); log_magenta("rambutan x %d\n", 15); log_cyan("Peeps x %d boxes\n", 5); return EXIT_SUCCESS; }
When you compile with-DDEBUG
, the output should look like this:you@ecegrid-thin1 ~/HW05 $
gcc -o test_clog test_clog.c -DDEBUG
you@ecegrid-thin1 ~/HW05 $
./test_clog
COLORS green red yellow blue magenta cyan SHOPPING LIST bok choy x 3 bunches tomatos x 5 lemon x 3 borage x 100 flowers rambutan x 15 Peeps x 5 boxesyou@ecegrid-thin1 ~/HW05 $
When you compile without-DDEBUG
, there should be no output, like this:you@ecegrid-thin1 ~/HW05 $
gcc -o test_clog test_clog.c
you@ecegrid-thin1 ~/HW05 $
-
How can I stop ANSI codes when redirecting to a file or another program?
This refers to the line in the Requirements table that states, “Do not print ANSI codes when output is being directed to a file or other application.”As mentioned just below that requirement, you can use theisatty(STDERR_FILENO)
function. It returns true if the output is going directly to the terminal, and false if the output is being redirected to a file or another program.The following snippet illustrates how that would work. This is one of several ways you could this. This is included only to help those who may be stuck on this part.#define __mu_log_color(color, ...) \ do { \ if(isatty(STDERR_FILENO)) { \ fprintf(stderr, "%s", color); \ } \ fprintf(stderr, __VA_ARGS__); \ if(isatty(STDERR_FILENO)) { \ fprintf(stderr, "%s", ANSI_RESET); \ } \ } while(false) // unavoidable hack for function-like macros (See Q6.)
Then, each of yourlog_COLOR(…)
functions would follow the following form:#define log_red(...) __mu_log_color(ANSI_RED, __VA_ARGS__)
… and so on. -
How can I test that it is working (i.e., no ANSI codes when output is redirected to a file or another program)?
One way to check is to redirect the output to a file and then open that file in Vim, or print its contents using the cat command.you@ecegrid-thin1 ~/HW05 $
gcc -o test_clog test_clog.c -DDEBUG
you@ecegrid-thin1 ~/HW05 $
./test_clog &> actual.txt
you@ecegrid-thin1 ~/HW05 $
cat actual.txt
COLORS green red yellow blue magenta cyan SHOPPING LIST bok choy x 3 bunches tomatos x 5 lemon x 3 borage x 100 flowers rambutan x 15 Peeps x 5 boxesyou@ecegrid-thin1 ~/HW05 $
Another way to check this is to redirect the output to thecat
command.you@ecegrid-thin1 ~/HW05 $
gcc -o test_clog test_clog.c -DDEBUG
you@ecegrid-thin1 ~/HW05 $
./test_clog | cat
COLORS green red yellow blue magenta cyan SHOPPING LIST bok choy x 3 bunches tomatos x 5 lemon x 3 borage x 100 flowers rambutan x 15 Peeps x 5 boxesyou@ecegrid-thin1 ~/HW05 $
-
I'm confused about
isatty(…)
and/or how to omit the ANSI color codes when output is going to a file or another program. What should I do?
This will be a small part of the score. If it isn't working for you, get the other parts working before worrying about this. -
Why is this even a requirement?
Vim (and other editors) can call make directly, and show you the output right in the editor. However, the color codes make a mess. More generally, this issue comes up in many programs that print in color (e.g.,ls
); not printing the ANSI codes to a non-terminal is standard behavior for command-line programs. -
How do I make
mu_run(…)
print the success/failure messages in color even when the DEBUG symbols is not defined (i.e.,-DDEBUG
not passed to GCC), and without duplicating the ANSI codes in miniunit.h?
Define a helper macro for printing in color outside the#ifdef/#endif
. You can use the one in Q12 or make your own. You will need to define the ANSI codes (#define ANSI_RED …
, etc.) outside the#ifdef/#endif
, as well. -
GCC: “ISO C99 requires rest arguments to be used.” ⋯???
In variadic macros (see Q3), the...
can stand for 1 or more arguments. If yourlog_red(…)
looks like#define log_red(format, ...) ▒▒▒▒▒▒▒▒▒▒
, it will likely work as long as you pass ≥2 arguments (e.g.,log_red("I like %d", 5)
), but if you pass only a string (e.g.,log_red("orange sky")
), then there are 0 arguments for the...
. It needs ≥1. The solution for our purposes is to remove the first argument (format
). The correct form was given in Q3 and Q12. -
GCC: “error: ‘true’ undeclared” ⋯???
GCC: “error: ‘false’ undeclared” ⋯???
Thetrue
andfalse
constants are defined in a standard header called stdbool.h; you need to include it (i.e.,#include <stdbool.h>
) in any file where you use them (e.g., clog.h). This was communicated in #8 of the Requirements table, as well as the Code Quality Standards, which have more aboutbool
,true
, andfalse
. -
GCC: “implicit declaration of function ‘isatty’” ⋯???
GCC “‘STDERR_FILENO’ undeclared” ⋯???
Theisatty(…)
function and STDERR_FILENO symbol are defined in a standard header called unistd.h you need to include it (i.e.,#include <unistd.h>
). This was communicated in #7 and #8 of the Requirements table. -
What is the purpose of the debug rule in the Makefile?
Compiling withmake debug
will enable yourlog_▒▒▒(…)
macros by passing the-DDEBUG
flag to GCC (i.e., to define theDEBUG
symbol). With justmake
(ormake test_count_words
)DEBUG
will not be defined, so yourlog_▒▒▒(…)
macros will be silent. How you callmake
determines whether they are on or off.After HW05, you are welcome to modify this (e.g., if you want yourlog_▒▒▒(…)
macros to be enabled by default.) -
Make: “No rule to make target `miniunit.h', needed by `debug'”?
You do not have a file called miniunit.h, but it is listed as a prerequisite of that file. -
After editing miniunit.h or clog.h, nothing changes when I run
make test
?
Make sure yourmake test
rule depends ondebug
. -
GCC: “__mu_failure_line_num is not defined” ⋯ Why?
If you get that withinmain(…)
, make sure you are not trying to use the variable declared inmu_start(…)
in yourmu_run(…)
. Yourmu_start(…)
is expanded in the context of a_test_▒▒▒(…)
function, whilemu_run(…)
is expanded in the context ofmain(…)
. -
CPP: "Unexpected EOF (end-of-file)" (or similar). Why?
You probably have unmatched braces somewhere in your clog.h or miniunit.h. First, fix your indents. It will make the errors more obvious. Then, be sure to use/usr/bin/cpp test_count_words.c | indent
to make the output readable. -
After changing the
printf(…)
statements in test_count_words.c tolog_int(…)
, runningmake test
prints the messages and the test itself doesn't work right.
It's okay.log_int(…)
prints tostderr
so the diff testing isn't seeing the output. It is going to the terminal. (This answer might be expanded later.) -
What else could be wrong with my clog.h?
Make sure you have parenthesized the condition parameter. The rationale was covered in both sections' lectures. See the slides. Failure to follow this has caused many students' errors and incorrect behavior.
Updates
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