properly comparing and finding difference between two structs with exported members using go-cmp

user_80932 0
Viewed 3028

I'm writing a Go application, and I want to create a test for it, in that test, I query something from the db, insert it into a struct, and compare that struct values with a static struct of the same type that I had, if they match, the test succeeded, if not, I wanna show the difference. so I'm trying to use go-cmp package.

In general I'm getting this error:

panic: cannot handle unexported field at {main.fooTest}.F1.Int.neg:
    "math/big".Int
consider using a custom Comparer; if you control the implementation of type, you can also consider using an Exporter, AllowUnexported, or cmpopts.IgnoreUnexported [recovered]

I'm getting this is because of the pgtype.Numeric that I have in my struct

type fooTest struct {
    I1   int
    I2   *int
    S1   string
    S2   *string
    F1   pgtype.Numeric
    F2   *pgtype.Numeric
    Ff1  float64
    Ff2  *float64
    Ia1  []int
    Ia2  []*int
    Ia3  *[]int
    Sa1  []string
    Sa2  []*string
    Sa3  *[]string
    Fa1  pgtype.Float8Array
    Fa2  *pgtype.Float8Array
    Faf1 []float64
    Faf2 []*float64
    Faf3 *[]float64
}

so I tried to test with `AllowUnnexported` but the `cmp.Equal` line still fails with that error.

if !cmp.Equal(fooFoo, bar,cmp.AllowUnexported(fooTest{})) {
            t.Errorf("failed test: %v",cmp.Diff(fooFoo, bar))
        }

any ideas how to resolve this ?

go-cmp go struct
2 Answers

Have you tried

cmp.Equal(fooFoo, bar, cmp.AllowUnexported(pgtype.Numeric.Int{}))

The documentation of AllowUnexported doesn't mention that it recursively applies this to all values in the struct.

user_42810770

I got panic: cannot handle unexported field at ... using cmp.Equal with unexported fields. This question popped on google but didn't help. Took my time, solved it and answered here for anyone needs.

user_77114540
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