In trying to test the following func:
//Transaction Begins a sql transaction.
func Transaction(db *sql.DB, txFunc func(*sql.Tx) *errors.ErrorSt) (retErrSt *errors.ErrorSt) {
retErrSt = nil
tx, retErrSt := beginTrans(db)
if retErrSt != nil {
return retErrSt
}
defer func() {
if p := recover(); p != nil {
tx.Rollback()
panic(p) // re-throw panic after Rollback
} else if retErrSt != nil {
tx.Rollback()
} else {
if err := tx.Commit(); err != nil {
retErrSt = errors.Database().AddDetails(err.Error())
}
}
}()
retErrSt = txFunc(tx)
return retErrSt
}
I make use of the sqlmock library to mock database actions. This has served me well thus far, but is causing regressions when I start piling on test cases.
Setup
My test setup is thus:
// database mock/stub setup
db, mock, err := sqlmock.New()
if !assert.Nilf(t,
err,
"Error on trying to start up a stub database connection") {
t.Fatal()
}
defer db.Close()
Test functions
To create this MVCE, I reduced it down to two tests. Both work when the other is commented out:
First Test
t.Run("WantCommitError", func(t *testing.T) {
// define sql behavior
mock.ExpectBegin()
err := Transaction(db,
func(tx *sql.Tx) *errors.ErrorSt {
return nil
})
defer func() {
mock.ExpectCommit().
WillReturnError(goErrors.New("test commit error"))
assert.Equal(t,
string(errors.ACDatabase),
err.Code)
}()
mock.ExpectationsWereMet()
})
Second Test
t.Run("WantErrorFromCallback", func(t *testing.T) {
mock.ExpectBegin()
err := Transaction(db,
func(tx *sql.Tx) *errors.ErrorSt { return new(errors.ErrorSt) })
defer func() {
mock.ExpectRollback()
}()
mock.ExpectationsWereMet()
if !assert.Equal(t, new(errors.ErrorSt), err) {
t.Error(err.ToString(false))
}
})
Problem
When I make sure that neither one is commented out, I get chaos. The message I get is thus:
Error Trace: dbConnectionsU_test.go:1859
Error: Not equal:
expected: &errors.ErrorSt{Code:"", Message:"", Scope:0, Severity:0, Details:errors.LoggerDetails(nil), InnerError:(*errors.ErrorSt)(nil), Stack:""}
actual : &errors.ErrorSt{Code:"db", Message:"", Scope:0, Severity:0, Details:errors.LoggerDetails{"call to database transaction Begin, was not expected, next expectation is: ExpectedCommit => expecting transaction Commit, which should return error: test commit error"}, InnerError:(*errors.ErrorSt)(nil), Stack:"
\tC:/Go/src/runtime/debug/stack.go:24 +0xae
ezsoft/apiserver_sdk/utilities/utilityCore.GetCleanStack(0xc042069470, 0x3, 0x3, 0x3, 0xc0420db8e8)
\tD:/dev2017/GO/src/ezsoft/apiserver_sdk/utilities/utilityCore/utilityCore.go:56 +0x3b
ezsoft/apiserver_sdk/db.beginTrans(0xc04204d360, 0x0, 0x0)
\tD:/dev2017/GO/src/ezsoft/apiserver_sdk/db/dbConnectionsU.go:365 +0x100
ezsoft/apiserver_sdk/db.Transaction(0xc04204d360, 0x821690, 0x0)
\tD:/dev2017/GO/src/ezsoft/apiserver_sdk/db/dbConnectionsU.go:443 +0x3f
ezsoft/apiserver_sdk/db.TestTransaction.func2(0xc0421363c0)
\tD:/dev2017/GO/src/ezsoft/apiserver_sdk/db/dbConnectionsU_test.go:1851 +0x75
testing.tRunner(0xc0421363c0, 0xc0420e48a0)
\tC:/Go/src/testing/testing.go:777 +0xd7
created by testing.(*T).Run
\tC:/Go/src/testing/testing.go:824 +0x2e7
"}
Diff:
--- Expected
+++ Actual
@@ -1,3 +1,3 @@
(*errors.ErrorSt)({
- Code: (string) "",
+ Code: (string) (len=2) "db",
Message: (string) "",
@@ -5,5 +5,7 @@
Severity: (errors.Severity) 0,
- Details: (errors.LoggerDetails) <nil>,
+ Details: (errors.LoggerDetails) (len=1) {
+ (string) (len=167) "call to database transaction Begin, was not expected, next expectation is: ExpectedCommit => expecting transaction Commit, which should return error: test commit error"
+ },
InnerError: (*errors.ErrorSt)(<nil>),
- Stack: (string) ""
+ Stack: (string) (len=788) "
\tC:/Go/src/runtime/debug/stack.go:24 +0xae
ezsoft/apiserver_sdk/utilities/utilityCore.GetCleanStack(0xc042069470, 0x3, 0x3, 0x3, 0xc0420db8e8)
\tD:/dev2017/GO/src/ezsoft/apiserver_sdk/utilities/utilityCore/utilityCore.go:56 +0x3b
ezsoft/apiserver_sdk/db.beginTrans(0xc04204d360, 0x0, 0x0)
\tD:/dev2017/GO/src/ezsoft/apiserver_sdk/db/dbConnectionsU.go:365 +0x100
ezsoft/apiserver_sdk/db.Transaction(0xc04204d360, 0x821690, 0x0)
\tD:/dev2017/GO/src/ezsoft/apiserver_sdk/db/dbConnectionsU.go:443 +0x3f
ezsoft/apiserver_sdk/db.TestTransaction.func2(0xc0421363c0)
\tD:/dev2017/GO/src/ezsoft/apiserver_sdk/db/dbConnectionsU_test.go:1851 +0x75
testing.tRunner(0xc0421363c0, 0xc0420e48a0)
\tC:/Go/src/testing/testing.go:777 +0xd7
created by testing.(*T).Run
\tC:/Go/src/testing/testing.go:824 +0x2e7
"
})
Test: TestTransaction/WantErrorFromCallback
It's acting like the calls to Begin were never expected, but in both cases, literally the first line of code is mock.ExpectBegin()!
I suspect it may have to deal with deferred code, both in the func under test and necessarily in my test code, but I don't know how to control for that. Furthermore, I'm not sure my suspicion is right.
