test_unit_t_digest.c File Reference

This file contains definitions and implementation of various unit tests for checking the functionality of the t_digest.c module. More...

#include <float.h>
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "configuration.h"
#include "cdi_logger_api.h"
#include "cdi_os_api.h"
#include "t_digest.h"
#include "utilities_api.h"

Macros
#define	TEST_URAND_SAMPLES   (300000)
	Define for the number of samples to run in the TestUniformRand test.
#define	TEST_SRAND_SAMPLES   (300)
	Define for the number of samples to run in the TestSkewedRand test.
#define	TEST_RUNTIME_SAMPLES   (200000000)
	Define for the number of samples to run in the TestRunTime test.
#define	TEST_NUM_PERCENTILES   (14)
	Define for the number of percentiles to check in this test.
#define	COMPARE_RETURN_MSG(message, test)   do { if (!(test)) return message; } while (0)
	Macro used to do a boolean test and return a message if the test fails.
#define	RUN_TEST(test, run_flag)
	Macro used to run a test function that returns a message; this macro returns that message if it is not NULL.
#define	MAX_FILE_LINES   (10000)
	Define to limit the number of lines of an input data file to read.
#define	USEC_PER_SEC   (1000000)
	Define for the number of microseconds in a second.

Functions
static int	SortComp (const void *c1_ptr, const void *c2_ptr)
	Function used by qsort to make decisions about how to sort.
static uint32_t	GetRandFromToSkewed (uint32_t min, uint32_t max)
	Function to get a random number within the range min to max, but to distribute the samples more closely around the 30% and 70% positions in that range as follows: 40% of samples are within 10% of the 30% point in the range. 40% of samples are within 10% of the 70% point in the range. 20% of the samples are randomly distributed across the entire range.
static uint32_t	GetRandFromTo (uint32_t min, uint32_t max)
	Function to get a random number within the range min to max.
static char *	TestGenericArray (TDigestHandle td_handle, uint32_t *data_array, int num_entries)
	This is a generic function that takes in a digest and an array of input samples and then adds all the samples to the digest and then checks some main percentile values for correctness.
static char *	TestSimple3 ()
	Simple test that adds 3 samples to the digest and then checks the percentile values.
static char *	TestSimple100 ()
	Simple test that adds 100 samples to the digest and then checks the percentile values.
static char *	TestRunTime ()
	Simple test that adds TEST_RUNTIME_SAMPLES uniform random samples to the digest and measures the amount of time it takes.
static char *	TestUniformRand ()
	Simple test that adds TEST_URAND_SAMPLES uniform random samples to the digest and then checks for percentile values.
static char *	TestSkewedRand ()
	Simple test that adds TEST_SRAND_SAMPLES skewed random samples to the digest and then checks for percentile values. "Skewed random samples" are samples that tend to be random within a certain range, with few outside that range. In this case, the function GetRandFromToSkewed() is used to generate a distribution with two main focal ranges and a lighter random distribution outside of those focal ranges.
static char *	TestRealDataFromFile ()
	This test reads input samples from a file and feeds them into the digest and then checks for expected percentile values. This is intended to allow users to collect their own data from an actual cdi_test test run and feed it in. The file must be in a format where each line is a sample.
static char *	TestInvalidPercentiles ()
	This test verifies that the value NaN is returned under certain known circumstances, such as when the digest is empty, or when a percentile outside of 0-100, inclusive, is requested.
static char *	AllTests ()
	Runs all tests. Use the boolean parameter after the test name to enable or disable tests.
bool	TestUnitTDigest (void)
	Public wrapper for AllTests() above.

Variables
static int	tests_run
	Variable used to count the number of tests that have been run.

Detailed Description

This file contains definitions and implementation of various unit tests for checking the functionality of the t_digest.c module.

Macro Definition Documentation

RUN_TEST

#define RUN_TEST	(		test,
			run_flag )

Value:

          do { if (run_flag) { char* message = test(); tests_run++; \
          if (message) { return message; } } } while (0)

Macro used to run a test function that returns a message; this macro returns that message if it is not NULL.

Function Documentation

AllTests()

static char * AllTests ( )

static

Runs all tests. Use the boolean parameter after the test name to enable or disable tests.

Returns

Message for a failure; NULL if no errors.

GetRandFromTo()

static uint32_t GetRandFromTo ( uint32_t min, uint32_t max )

static

Function to get a random number within the range min to max.

Parameters

min	The minimum allowable number.
max	The maximum allowable number.

Returns

A random float number within the desired range.

GetRandFromToSkewed()

static uint32_t GetRandFromToSkewed ( uint32_t min, uint32_t max )

static

Function to get a random number within the range min to max, but to distribute the samples more closely around the 30% and 70% positions in that range as follows: 40% of samples are within 10% of the 30% point in the range. 40% of samples are within 10% of the 70% point in the range. 20% of the samples are randomly distributed across the entire range.

Parameters

min	The minimum allowable number.
max	The maximum allowable number.

Returns

A random float number with the desired distribution within the specified range.

SortComp()

static int SortComp ( const void * c1_ptr, const void * c2_ptr )

static

Function used by qsort to make decisions about how to sort.

Parameters

c1_ptr	Pointer to the first value to sort.
c2_ptr	Pointer to the second value to sort.

Returns

-1 if c1 < c2, 1 if c1 > c2, and 0 if they are equal.

TestGenericArray()

static char * TestGenericArray ( TDigestHandle td_handle, uint32_t * data_array, int num_entries )

static

This is a generic function that takes in a digest and an array of input samples and then adds all the samples to the digest and then checks some main percentile values for correctness.

Parameters

td_handle	Pointer to the t-Digest instance to use for this test.
data_array	The array of input samples.
num_entries	The number of input samples in the data_array.

Returns

Message for a failure; NULL if no errors.

TestInvalidPercentiles()

static char * TestInvalidPercentiles ( )

static

This test verifies that the value NaN is returned under certain known circumstances, such as when the digest is empty, or when a percentile outside of 0-100, inclusive, is requested.

Returns

Message for a failure; NULL if no errors.

TestRealDataFromFile()

static char * TestRealDataFromFile ( )

static

This test reads input samples from a file and feeds them into the digest and then checks for expected percentile values. This is intended to allow users to collect their own data from an actual cdi_test test run and feed it in. The file must be in a format where each line is a sample.

Returns

Message for a failure; NULL if no errors.

TestRunTime()

static char * TestRunTime ( )

static

Simple test that adds TEST_RUNTIME_SAMPLES uniform random samples to the digest and measures the amount of time it takes.

Returns

Message for a failure; NULL if no errors.

TestSimple100()

static char * TestSimple100 ( )

static

Simple test that adds 100 samples to the digest and then checks the percentile values.

Returns

Message for a failure; NULL if no errors.

TestSimple3()

static char * TestSimple3 ( )

static

Simple test that adds 3 samples to the digest and then checks the percentile values.

Returns

Message for a failure; NULL if no errors.

TestSkewedRand()

static char * TestSkewedRand ( )

static

Simple test that adds TEST_SRAND_SAMPLES skewed random samples to the digest and then checks for percentile values. "Skewed random samples" are samples that tend to be random within a certain range, with few outside that range. In this case, the function GetRandFromToSkewed() is used to generate a distribution with two main focal ranges and a lighter random distribution outside of those focal ranges.

Returns

Message for a failure; NULL if no errors.

TestUniformRand()

static char * TestUniformRand ( )

static

Simple test that adds TEST_URAND_SAMPLES uniform random samples to the digest and then checks for percentile values.

Returns

Message for a failure; NULL if no errors.

TestUnitTDigest()

bool TestUnitTDigest

(

void

)

Public wrapper for AllTests() above.

External declarations.

Returns

Status code.