Getting unexpected error while executing queries for unit testing with sqlmock - unit-testing

Question

I have the following function that takes a slice of type SchoolDbEntry and bulk inserts it into a DB.
type SchoolRegistry struct {
Conn *sqlx.DB
}
insertStudentEntry = `insert into StudentEntries (registerId, studentId, fee, admissionDate) values (:registerId, :studentId, :fee, :admissionDate)`
func (s *SchoolRegistry) AddStudentEntries(ctx context.Context, entry []StudentDbEntry) error {
requestHeaders := helper.FetchHeaders(ctx)
query, args, err := sqlx.Named(insertStudentEntry, entry)
if err != nil {
return exception.DBInternalError
}
_, err = s.Conn.Exec(query, args...)
if err != nil {
return cutomModels.NewError(err.Error()
}
return nil
}
I am trying to test this using sqlmock using the following functions
var repo *SchoolRegistry
func TestAddStudentEntriesSuccess(t *testing.T) {
db, mock, err := sqlmock.New()
if err != nil {
t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
}
sqlxDb := sqlx.NewDb(db, "sqlmock")
defer sqlxDb.Close()
repo = &SchoolRegistry{sqlxDb}
if err := logger.Init(logLevel, logTimeFormat); err != nil {
fmt.Printf("failed to initialize logger: %v", err)
}
query := `insert into StudentEntries (registerId, studentId, fee, admissionDate) values (:registerId, :studentId, :fee, :admissionDate)`
args := []models.StudentDbEntry{
{
RegisterID: 1,
StudentID: 1,
Fee: "100",
AdmissionDate: "10-20-2015",
},
}
prep := mock.ExpectPrepare(query)
prep.ExpectExec().WithArgs(1,1,"100","10-20-2015").WillReturnResult(sqlmock.NewResult(0, 0))
err := repo.AddStudentEntries(helper.FetchTestContext(), args)
assert.NoError(t, err)
}
However, the tests are failing. I am getting
call to ExecQuery 'insert into StudentEntries (registerId, studentId, fee, admissionDate) values (?, ?, ?, ?)' with args [{Name: Ordinal:1 Value:1} {Name: Ordinal:2 Value:1} {Name: Ordinal:3 Value:"100"} {Name: Ordinal:4 Value:"10-20-2015"}], was not expected, next expectation is: ExpectedPrepare => expecting Prepare statement which:
- matches sql: 'insert into StudentEntries (registerId, studentId, fee, admissionDate) values (:registerId, :studentId, :fee, :admissionDate)'
error when no errors are expected ( that is, after this line : _, err = s.Conn.Exec(query, args...) ). The function works fine when I tested it as a part of the actual code. The issue is just with the unit testing.