Strange Google Test error with floating point numbers
I am having trouble testing floating point values for equality since Google Test 1.7.0.
My statement looks like this:
ASSERT_NEAR(124691356.375f, actual, DELTA);
The test fails with the following error:
The difference between 124691356.375f and the actual value is 3.625, which is higher than the DELTA, where 124691356.375f is valued to 124691360 , the actual estimate is 124691356.375 and the DELTA is 0.0625.
What's happening? actual
, and the expected result is clearly within the 0.0625 allowable error. Why does gtest evaluate a floating point literal 124691356.375f
this way?
Update: DELTA
and actual
are of type double and the expected value is a floating point literal. If I change the literal to be a double, or change other arguments to be float (so that everything is of the same type), the test passes. The question still remains - what causes this behavior when the types do not match?
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124691356.375f
is a single precision floating point number that has 7 to 8 significant decimal digits. Therefore, it is "rounded" to 124691360, which is not a valid error. You must use 124691356.375lf
. See also wikipedia and this question .
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