Added stderr capture split into a new file.

README.md

@@ -14,6 +14,9 @@ need this guard:
 Tests are defined with the `TEST` macro. You may also use the `GLOBALS`,
 `SET_UP` and `TEAR_DOWN` macros to centralize your initializations.
 
+There are additional helpers in the `cheat_helpers.h` file, which provide
+stuff to help you test some harder to test stuff.
+
 ---
 
 CHEAT is Copyrighted (c) 2012 Guillermo "Tordek" Freschi.

cheat.h

@@ -59,6 +59,7 @@ static void cheat_suite_init(struct cheat_test_suite *suite)
 
 static void cheat_suite_cleanup(struct cheat_test_suite *suite)
 {
+    (void) suite;
 }
 
 static void cheat_suite_summary(struct cheat_test_suite *suite)
@@ -154,6 +155,9 @@ int main(int argc, char *argv[])
 
     cheat_test **current_test = tests;
 
+    (void) argc;
+    (void) argv;
+
     cheat_suite_init(&suite);
 
     while (*current_test) {
@@ -189,6 +193,6 @@ int main(int argc, char *argv[])
 #define TEAR_DOWN(body) static void cheat_tear_down() body
 #define GLOBALS(body) body
 
-#define cheat_assert(assertion) cheat_test_assert(suite, assertion, #assertion, __FILE__, __LINE__);
+#define cheat_assert(assertion) cheat_test_assert(suite, assertion, #assertion, __FILE__, __LINE__)
 
 #endif

cheat_helpers.h

@@ -9,31 +9,38 @@
 
 #include <unistd.h>
 
-#define TEST_WITH_CAPTURED_STDOUT(name, body) TEST(name, {\
-        fflush(stdout);\
-        char filename_pattern[] = "cheat_captured_stdout_" #name "_XXXXXX";\
-        int original_stdout;\
-        int fake_stdout;\
-        original_stdout = dup(STDOUT_FILENO); \
-        fake_stdout = mkstemp(filename_pattern);\
-        dup2(fake_stdout, STDOUT_FILENO);\
-        { body }\
-        fflush(stdout);\
-        dup2(original_stdout, STDOUT_FILENO); \
-        })
-
-int cheat_stdout_contains(char *contents)
+#define CHEAT_WRAP_STREAM(stream, stream_fd, name, body) \
+        char filename_pattern[] = "cheat_captured_stream_" #name "_XXXXXX";\
+        int original_stream;\
+        int fake_stream;\
+        fflush(stream);\
+        original_stream = dup(stream_fd); \
+        fake_stream = mkstemp(filename_pattern);\
+        dup2(fake_stream, stream_fd);\
+        setbuf(stream, NULL);\
+        body\
+        fflush(stream);\
+        dup2(original_stream, stream_fd);
+
+#define TEST_WITH_CAPTURED_STDOUT(name, body) TEST(name, { CHEAT_WRAP_STREAM(stdout, STDOUT_FILENO, name, body) } )
+#define TEST_WITH_CAPTURED_STDERR(name, body) TEST(name, { CHEAT_WRAP_STREAM(stderr, STDERR_FILENO, name, body) } )
+#define TEST_WITH_CAPTURED_OUTPUT(name, body) TEST(name, {\
+        CHEAT_WRAP_STREAM(stderr, STDERR_FILENO, name,\
+            CHEAT_WRAP_STREAM(stdout, STDOUT_FILENO, name, body)\
+        ))
+
+int cheat_stream_contains(FILE *stream, char *contents)
 {
     char *buffer;
     int result;
     int len;
 
-    fflush(stdout);
-    len  = lseek(STDOUT_FILENO, 0, SEEK_CUR);
-    lseek(STDOUT_FILENO, 0, SEEK_SET);
+    len = ftell(stream);
+    fseek(stream, 0, SEEK_SET);
+
     buffer = malloc(len + 1);
+    fread(buffer, 1, len, stream);
 
-    read(STDOUT_FILENO, buffer, len);
     result = strstr(buffer, contents) != NULL;
 
     free(buffer);

sampletest.c

@@ -48,11 +48,16 @@ TEST(second_failute, {
 
 TEST_WITH_CAPTURED_STDOUT(output_capture, {
     printf("Something stupid");
-    cheat_assert(cheat_stdout_contains("Something"));
+    cheat_assert(cheat_stream_contains(stdout, "Something"));
 })
 
 TEST_WITH_CAPTURED_STDOUT(large_output_captute, {
     printf("%1000s", "Potato");
 
-    cheat_assert(cheat_stdout_contains("Potato"));
+    cheat_assert(cheat_stream_contains(stdout, "Potato"));
+})
+
+TEST_WITH_CAPTURED_STDERR(stderr_capture, {
+    fprintf(stderr, "You can also capture errors!");
+    cheat_assert(cheat_stream_contains(stderr, "errors"));
 })