Robert, Advanced googletest Topics
Floating-Point Comparison Comparing floating-point numbers is tricky. Due to round-off errors, it is very unlikely that two floating-points will match exactly. Therefore, ASSERT_EQ 's naive comparison usually doesn't work. And since floating-points can have a wide value range, no single fixed error bound works. It's better to compare by a fixed relative error bound, except for values close to 0 due to the loss of precision there. In general, for floating-point comparison to make sense, the user needs to carefully choose the error bound. If they don't want or care to, comparing in terms of Units in the Last Place (ULPs) is a good default, and googletest provides assertions to do this. ASSERT_FLOAT_EQ(val1, val2); EXPECT_FLOAT_EQ(val1, val2); the two float values are almost equal ASSERT_DOUBLE_EQ(val1, val2); EXPECT_DOUBLE_EQ(val1, val2); the two double values are almost equal By "almost equal" we mean the values are within 4 ULP's from each other. What does testify do? Peter On Monday, February 1, 2021 at 12:14:35 AM UTC-5 Robert M. Münch wrote: > I have a C library with some test-cases (using googletest) that all pass. > I created Go bindings for the C lib and converted the tests to testify > format. > > Some Go test fails because a return value from the C function (type float) > is different than expected. For example: > > ASSERT_FLOAT_EQ(10, GetHeight(root)); // C code works > > assert.EqualValues(t, 10, root.Height()) // Go code fails > The returned value in Go is: float32(1e+21) instead of float32(10). I'm > really wondering how this can happen. It looks like somewhere in the FFI, > the value changes. But what puzzles me, I'm using the same Go tests over > and over in other tests, and things are working. > > Does anyone have an idea what could be the problem? > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/cc7cbf40-55c4-4949-92f3-925577ebff4cn%40googlegroups.com.
