QtTest. How to compare double numbers

Hi everybody

I want to compare double numbers like in CppUnit: CPPUNIT_ASSERT_DOUBLES_EQUAL(expected, actual, delta)

Thanks

Ivan

Code:

---

QCOMPARE(expected+1, actual+1);

---

I want to compare with 'delta'. Because I have double numbers

Output:

Code:

---

Starting C:\Users\Ivan\qt_projects\TestSphere\debug\TestSphere.exe...
********* Start testing of TestSphere *********
Config: Using QTest library 4.8.1, Qt 4.8.1
PASS   : TestSphere::initTestCase()
FAIL!  : TestSphere::testCalcArea() Compared doubles are not the same (fuzzy compare)
   Actual (s.calcArea(6)): 452.389
   Expected (452.389): 452.389
testsphere.cpp(9) : failure location
FAIL!  : TestSphere::testCalcVolume() Compared doubles are not the same (fuzzy compare)
   Actual (s.calcVolume(6)): 904.779
   Expected (904.779): 904.779
testsphere.cpp(18) : failure location
PASS   : TestSphere::cleanupTestCase()
Totals: 2 passed, 2 failed, 0 skipped
********* Finished testing of TestSphere *********
********* Start testing of TestSphere *********
Config: Using QTest library 4.8.1, Qt 4.8.1
PASS   : TestSphere::initTestCase()
FAIL!  : TestSphere::testCalcArea() Compared doubles are not the same (fuzzy compare)
   Actual (s.calcArea(6)): 452.389
   Expected (452.389): 452.389
testsphere.cpp(9) : failure location
FAIL!  : TestSphere::testCalcVolume() Compared doubles are not the same (fuzzy compare)
   Actual (s.calcVolume(6)): 904.779
   Expected (904.779): 904.779
testsphere.cpp(18) : failure location
PASS   : TestSphere::cleanupTestCase()
Totals: 2 passed, 2 failed, 0 skipped
********* Finished testing of TestSphere *********
C:\Users\Ivan\qt_projects\TestSphere\debug\TestSphere.exe exited with code 2

---

This is my code:

TestSphere.pro

Code:

---

SOURCES += \
    main.cpp \
    testsphere.cpp \
    sphere.cpp
 
HEADERS += \
    testsphere.h \
    sphere.h
 
CONFIG += \
    qtestlib console

---

main.cpp

Code:

---

#include <QtTest>
#include "testsphere.h"
 
QTEST_MAIN(TestSphere)

---

testsphere.h

Code:

---

#ifndef TESTSPHERE_H
#define TESTSPHERE_H
 
#include <QObject>
 
class TestSphere : public QObject
{
    Q_OBJECT
 
private slots:
    void testCalcArea();
    void testCalcVolume();
};
 
#endif // TESTSPHERE_H

---

testsphere.cpp

Code:

---

#include <QtTest>
#include "sphere.h"
#include "testsphere.h"
 
void TestSphere::testCalcArea()
{
    Sphere s;
 
    QCOMPARE(s.calcArea(6), 452.389);
    QCOMPARE(s.calcArea(7), 615.752);
    QCOMPARE(s.calcArea(8), 804.2477);
}
 
void TestSphere::testCalcVolume()
{
    Sphere s;
 
    QCOMPARE(s.calcVolume(6), 904.779);
    QCOMPARE(s.calcVolume(7), 1436.755);
    QCOMPARE(s.calcVolume(8), 2144.661);
}

---

sphere.h

Code:

---

#ifndef SPHERE_H
#define	SPHERE_H
 
class Sphere {
public:
    Sphere();
    double calcArea(double r);
    double calcVolume(double r);
private:
    double area;
    double volume;
};
 
#endif	/* SPHERE_H */

---

sphere.cpp

Code:

---

#include "sphere.h"
#include <cmath>
 
Sphere::Sphere() {
    area = 0;
    volume = 0;
}
 
double Sphere::calcArea(double r) {
    area = 4.0 * M_PI * pow(r, 2.0);
    return area;
}
 
double Sphere::calcVolume(double r) {
    volume = (4.0/3.0) * M_PI * pow(r, 3.0);
    return volume;
}

---

Then compare with delta.

qFuzzyCompare has an internal delta it uses but if you want your own then simply do this:

Code:

---

QVERIFY(actual-delta <= expected && actual+delta >=expected)

---

This is qFuzzyCompare:

Code:

---

static inline bool qFuzzyCompare(double p1, double p2)
{
    return (qAbs(p1 - p2) <= 0.000000000001 * qMin(qAbs(p1), qAbs(p2)));
}

---

You can implement your own function that takes the delta as a parameter.

Thank you very much!