tests/driver_sht2x: avoid negative number after decimal dot

[keestux]

This is a similar fix as in #12162 and #12140.

[keestux]

Notice that sht3x has a similar problem too. But that one has a bug as well, I think.

[benpicco]

The same logic as in the other two PRs applies.

[keestux]

In the sht3x test there is this:

        int16_t temp;
        int16_t hum;

        if ((res = sht3x_read(&dev, &temp, &hum)) == SHT3X_OK) {
            printf("Temperature [°C]: %d.%d\n"
                   "Relative Humidity [%%]: %d.%d\n"
                   "+-------------------------------------+\n",
                   temp / 100, temp % 100,
                   hum / 100, hum % 100);
        }

Not only does it need an abs() for the numbers after decimal dot, it has %d for a 2 digit number. This means that a temperature of 10.05 degrees will be printed as 10.5. Same for the humidity. I don't have the device so I can't really test.

[benpicco]

I don't have the device so I can't really test.

I mean the format string is device independent, no?
If we assume the documentation is right, temp will be

Temperature in hundredths of a degree Celsius

so we can set int16_t temp = -1005; and test the behavior of printf() locally.

[aabadie]

There's indeed a problem, the formatter for temperature should be %d.%02d (also tested this locally).

[aabadie]

There's indeed a problem, the formatter for temperature should be %d.%02d (also tested this locally).

well, in fact it's not needed since the number after decimal dot is divided by 10. But this division could be removed if you use %d.%02d. This should be better.
I checked and bmx280 driver application has the same behaviour.