sql.Out values are not set by mock database

[jwenz723]

I have a query that I run that has a few sql.Out parameters. Using go-sqlmock, it doesn't appear to be possible to have values injected into the Dest field of a sql.Out parameter when the query is executed.

174 added some functionality to make some sql.Out testing possible, but it doesn't appear to be possible to fully test these types of queries.

For example, here is my query I have in my code:

func (r mgRepo) ExecuteQuery(ctx context.Context, area model.Area, cluster string, requestCount int64) (*MyGlobalData, error) {
    var AvailableRangeStart int64
    var IDBlockSize int64
    _, err := r.db.QueryContext(
        ctx,
        r.sProc,
        sql.Named("TableName", area.String()),
        sql.Named("MinBlockSize", requestCount),
        sql.Named("AvailableRangeStart", sql.Out{Dest: &AvailableRangeStart}),
        sql.Named("IDBlockSize", sql.Out{Dest: &IDBlockSize}),
        sql.Named("RequestingServer", cluster),
    )
    if err != nil {
        return nil, err
    }
    if AvailableRangeStart == 0 || IDBlockSize == 0 {
        return nil, errors.New("failed to retrieve block")
    }
    return &MyGlobalData{
        RangeStart: AvailableRangeStart,
        RangeEnd:   AvailableRangeStart + IDBlockSize - 1,
    }, nil
}

This function validates that the AvailableRangeStart and IDBlockSize sql.Out parameters have been assigned (checks that they don't have the default value of 0), which means I can't run this function using a mock database without the errors.New("failed to retrieve block") error being returned.

Here is my test:

type CustomConverter struct{}

func (s CustomConverter) ConvertValue(v interface{}) (driver.Value, error) {
    if val, ok1 := v.(driver.NamedValue); ok1 {
        return val.Value, nil
    }

    if val, ok := v.(sql.Out); ok {
        res := val.Dest.(*int64)
        return *res, nil
    }
    return v, nil
}

func TestMgRepo_ExecuteQuery(t *testing.T) {
    converter := sqlmock.ValueConverterOption(CustomConverter{})
    db, mock, err := sqlmock.New(converter)
    if err != nil {
        t.Errorf("failed to create sql mock")
    }

    a := int64(100)
    i := int64(10)

    mock.ExpectQuery("test").WithArgs(
        sql.Named("TableName", "Contact_log"),
        sql.Named("MinBlockSize", int64(10)),
        sql.Named("AvailableRangeStart", sql.Out{Dest: &a}),
        sql.Named("IDBlockSize", sql.Out{Dest: &i}),
        sql.Named("RequestingServer", "test"),
    ).WillReturnRows(nil)
    mgRepo := mgRepo{
        db:    db,
        sProc: "test",
    }
    _, err = mgRepo.ExecuteQuery(context.Background(), model.Contact_log, "test", int64(10))
    assert.Nil(t, err)
}

Here is the test execution output:

=== RUN   TestMgRepo_ExecuteQuery
--- FAIL: TestMgRepo_ExecuteQuery (0.00s)
    myGlobal_test.go:164: 
            Error Trace:    myGlobal_test.go:164
            Error:          Expected nil, but got: &errors.errorString{s:"Query 'test', arguments do not match: argument 2 expected [int64 - 100] does not match actual [int64 - 0]"}
            Test:           TestMgRepo_ExecuteQuery
FAIL

[l3pp4rd]

Hi, maybe you can try and investigate what change needs to be added and submit a PR.