Re: [Tarantool-patches] [PATCH 7/7] test/unit: add popen test

[Alexander Turenko <alexander.turenko@tarantool.org>]

There are two good properties, which can be easily achieved for the
test:

* better fit TAP13 format;
* set a non-zero exit code at fail.

See below (comments 2 and 4) if you're interested or skip if not.

There also two comments around (1 and 3), see them below too.

WBR, Alexander Turenko.

> +static int
> +main_f(va_list ap)
> +{
> +	int rc = 0;
> +
> +	rc = popen_write_exit();
> +	if (rc == 0)
> +		rc = popen_read_exit();
> +	if (rc == 0)
> +		rc = popen_kill();

1. I would run all tests even if some of them fails: this way we can get
   more info what is healthy and what is broken. And it is usual for
   TAP13 tests as I see.

> +
> +	ev_break(loop(), EVBREAK_ALL);
> +	return 0;
> +}

2. Since our unit.[ch] module supports test nesting I would start the
   function from plan() + header() prologue and end it with footer() +
   check_plan() epilogue. See swim.c or uri.c unit tests for example.

   This will make the output almost TAP13 compliant (now it contains
   several plans on one nesting level) and I hope we'll make it fully
   compliant by a change in unit.[ch] and remove most of *.result files
   in test/unit directory.

   I propose also save the check_plan() return value in a global static
   variable like in swim.c unit test to report it in the exit code of
   the process.

> +int
> +main(int argc, char *argv[])
> +{
> +	//say_logger_init(NULL, S_DEBUG, 0, "plain", 0);
> +	memory_init();
> +
> +	fiber_init(fiber_c_invoke);
> +	popen_init();
> +	coio_init();
> +	coio_enable();
> +
> +	if (!loop())
> +		panic("%s", "can't init event loop");
> +
> +	struct fiber *test = fiber_new("coio_stat", main_f);

3. It seems the name was copied from coio.cc and forgotten to change.
   AFAIS, it is usually "main" for such tests.

> +	fiber_wakeup(test);
> +
> +	ev_now_update(loop());
> +	ev_run(loop(), 0);
> +	popen_free();
> +	fiber_free();
> +	memory_free();
> +
> +	return 0;
> +}

4. I would return a return value from check_plan() in main_f() here,
   like in swim.c unit test.

   I think that it is good property to report a non-zero exit code from
   a test if it fails in some way, because this way we may relax
   requirements for a testing harness if we'll need it for some reason.

----

In fact I experimented around this and made the proposed changes. So
I'll share it with you in order to better show what I propose.

I also verified that after small changes in test/unit/unit.[ch] and the
changes below the result file for popen test can be deleted at all.

diff --git a/test/unit/popen.c b/test/unit/popen.c
index 7656ebe73..a40ca514c 100644
--- a/test/unit/popen.c
+++ b/test/unit/popen.c
@@ -16,6 +16,11 @@
 	POPEN_FLAG_SHELL		|	\
 	POPEN_FLAG_RESTORE_SIGNALS)
 
+/**
+ * A real return value of main_f(), see a comment in swim.c.
+ */
+static int test_result = 1;
+
 static int
 wait_exit(struct popen_handle *handle, int *state, int *exit_code)
 {
@@ -30,7 +35,7 @@ wait_exit(struct popen_handle *handle, int *state, int *exit_code)
 	return 0;
 }
 
-static int
+static void
 popen_write_exit(void)
 {
 	struct popen_handle *handle;
@@ -95,10 +100,10 @@ out_kill:
 
 out:
 	footer();
-	return check_plan();
+	check_plan();
 }
 
-static int
+static void
 popen_read_exit(void)
 {
 	struct popen_handle *handle;
@@ -152,10 +157,10 @@ out_kill:
 
 out:
 	footer();
-	return check_plan();
+	check_plan();
 }
 
-static int
+static void
 popen_kill(void)
 {
 	struct popen_handle *handle;
@@ -205,21 +210,24 @@ out_kill:
 
 out:
 	footer();
-	return check_plan();
+	check_plan();
 }
 
 static int
 main_f(va_list ap)
 {
-	int rc = 0;
+	plan(3);
+	header();
 
-	rc = popen_write_exit();
-	if (rc == 0)
-		rc = popen_read_exit();
-	if (rc == 0)
-		rc = popen_kill();
+	popen_write_exit();
+	popen_read_exit();
+	popen_kill();
 
 	ev_break(loop(), EVBREAK_ALL);
+
+	footer();
+	test_result = check_plan();
+
 	return 0;
 }
 
@@ -237,7 +245,7 @@ main(int argc, char *argv[])
 	if (!loop())
 		panic("%s", "can't init event loop");
 
-	struct fiber *test = fiber_new("coio_stat", main_f);
+	struct fiber *test = fiber_new("main", main_f);
 	fiber_wakeup(test);
 
 	ev_now_update(loop());
@@ -246,5 +254,5 @@ main(int argc, char *argv[])
 	fiber_free();
 	memory_free();
 
-	return 0;
+	return test_result;
 }