I am currently trying to test a piece of my code that runs a query on the datastore before putting in a new entity to ensure that duplicates are not created. The code I wrote works fine in the context of the app, but the tests I wrote for that methods are failing. It seems that I cannot access data put into the datastore through queries in the context of the testing package.
One possibility might lie in the output from goapp test which reads: Applying all pending transactions and saving the datastore. This line prints out after both the get and put methods are called (I verified this with log statements).
I tried closing the context and creating a new one for the different operations, but unfortunately that didn't help either. Below is a simple test case that Puts in an object and then runs a query on it. Any help would be appreciated.
type Entity struct {
Value string
}
func TestEntityQuery(t *testing.T) {
c, err := aetest.NewContext(nil)
if err != nil {
t.Fatal(err)
}
defer c.Close()
key := datastore.NewIncompleteKey(c, "Entity", nil)
key, err = datastore.Put(c, key, &Entity{Value: "test"})
if err != nil {
t.Fatal(err)
}
q := datastore.NewQuery("Entity").Filter("Value =", "test")
var entities []Entity
keys, err := q.GetAll(c, &entities)
if err != nil {
t.Fatal(err)
}
if len(keys) == 0 {
t.Error("No keys found in query")
}
if len(entities) == 0 {
t.Error("No entities found in query")
}
}
There is nothing wrong with your test code. The issue lies in the Datastore itself. Most queries in the HR Datastore are not "immediately consistent" but eventually consistent. You can read more about this in the Datastore documentation.
So basically what happens is that you put an entity into the Datastore, and the SDK's Datastore "simulates" the latency that you can observe in production, so if you run a query right after that (which is not an ancestor query), the query result will not include the new entity you just saved.
If you put a few seconds sleep between the datastore.Put() and q.GetAll(), you will see the test passes. Try it. In my test it was enough to sleep just 100ms, and the test always passed. But when writing tests for such cases, use the StronglyConsistentDatastore: true option as can be seen in JonhGB's answer.
You would also see the test pass without sleep if you'd use Ancestor queries because they are strongly consistent.
The way to do this is to force the datastore to be strongly consistent by setting up the context like this:
c, err := aetest.NewContext(&aetest.Options{StronglyConsistentDatastore: true})
if err != nil {
t.Fatal(err)
}
Now the datastore won't need any sleep to work, which is faster, and better practice in general.
Update: This only works with the old aetest package which was imported via appengine/aetest. It does not work with the newer aetest package which is imported with google.golang.org/appengine/aetest. App Engine has changed from using an appengine.Context to using a context.Context, and consequently the way that the test package now works is quite different.
To compliment #JohnGB's answer in the latest version of aetest, there are more steps to get a context with strong consistency. First create an instance, then create a request from that instance, which you can use to produce a context.
inst, err := aetest.NewInstance(
&aetest.Options{StronglyConsistentDatastore: true})
if err != nil {
t.Fatal(err)
}
defer inst.Close()
req, err := inst.NewRequest("GET", "/", nil)
if err != nil {
t.Fatal(err)
}
ctx := appengine.NewContext(req)
Related
I have following code
func (s *MyRepo) InsertOrder(ctx context.Context, orderID string) error {
query := `INSERT INTO orders (orderID) VALUES (?)`
stmt, err := s.db.RawDatabase().PrepareContext(ctx, query)
if err != nil {
return err
}
defer stmt.Close()
_, err = stmt.ExecContext(ctx, orderID)
if err != nil {
//log err
}
return err
}
And the corresponding test case is
func TestMyRepo_InsertOrder_Success(t *testing.T) {
orderID := "orderID"
mockDB, repo := getDBStore()
query := `[INSERT INTO orders (orderID) VALUES (?)]`
mockDB.ExpectPrepare(query).
ExpectExec().
WithArgs(orderID).
WillReturnResult(sqlmock.NewResult(1, 1)).
WillReturnError(nil)
err := repo.InsertOrder(context.Background(), orderID)
assert.Nil(t, err)
}
But this doesn't test if defer stmt.Close() has been called or not (which gets called once the function ends). How can I test this?
It looks like you are making use of data-dog's sqlmock package, so you ought to be able to use ExpectClose() to register the expectation that the database will be closed, and ExpectationsWereMet() to collect this information.
If you're using some other package, feel free to link it; there's probably something similar available, and worst-case you can write your own wrapper around their wrapper. Making sure that a particular method of a particular dependency was called is a fairly common desire when developers write tests using mocks, so most of the better mock packages will go out of their way to provide some sort of API to check that.
As noted in the comments on this question, tests of this nature are often of somewhat questionable value and can seem like they exist more to increase a dubious metric like % code coverage than to increase code reliability or maintainability.
Data streaming fails with BigQuery
It took 1,000 daunting inserts at the streaming insert, and it suddenly failed today. Why do not you know why you failed?
In the log, "[1 row insertion failed]"
That's all.
It looks like you're doing streaming inserts in Go using the package cloud.google.com/go/bigquery.
The method Inserter.Put() returns a PutMultiError when something goes wrong. PutMultiError is responsible for the message you saw. If you want to see more detail about the failure, you have to look at each sub-error separately. Something like this:
err := uploader.Put(ctx, rows)
switch e := err.(type) {
case bigquery.PutMultiError:
rowInsertionError := e[0] // the first failed row
for _, err := range rowInsertionError.Errors {
log.Printf("err = %v", err)
}
}
I have a method which implements the a database interface, that method inserts an 'object' into the database.
type database interface {
createLog(logDoc) (bool, error)
}
type mongo struct {
database string
collection string
}
func (m mongo) createLog(l logDoc) (bool, error) {
s, err := mgo.Dial("mongo")
defer s.Close()
if err != nil {
return false, err
}
err = s.DB(m.database).C(m.collection).Insert(l)
if err != nil {
return false, err
}
return true, nil
}
I want to be able to test the createLog method, how can I do this? should it be an integration test? if so what would be the your approach?
Thank you in advance
I just thought after watching the video & pondering this for a little bit and if nobody answered I would answer my own question.
This video resulted me in not writing any integration tests, rather writing unit tests. and creating stubs which allowed me to modify the way the interface behaved allowing me to tests when the database behaves correctly and incorrectly.
If you can think of a better way of describing what I said then please do :)
I am creating a web application that lists applicants and their position on a waiting list.
We need to be able to add new applicants to this list and remove applicants from the list. There will be under 10k applicants in the list.
Specifics:
I plan to write the app in Golang.
The list needs to be safe, I the program shuts down, it should be recoverable.
The app should contain this data for every applicant: Name, Student ID, position.
Questions:
How do I secure the list (lock?) so it is updated correctly for both if two updates to it is made at the same time?
Should I save the data in a database or use a file?
I need your help!
UPDATE:
Mockup code:
package main
import (
"log"
"sync"
"time"
"github.com/boltdb/bolt"
)
type applicant struct {
FirstName string
LastName string
StudentID string
Position int
}
type priorityList struct {
sync.Mutex
applicants []applicant
}
func (l *priorityList) newApplicant(fn string, ln string, sid string) error {
// add applicant to priorityList
return nil
}
func (l *priorityList) removeApplicant(sid string) error {
// remove applicant from priorityList
return nil
}
func (l *priorityList) editApplicant(sid string) error {
// edit applicant in priorityList
return nil
}
func main() {
// Database
db, err := bolt.Open("priorityList.db", 0600, &bolt.Options{Timeout: 1 * time.Second})
if err != nil {
log.Fatal(err)
}
defer db.Close()
}
If you use a file, you could use a Mutex to block concurrent writes.
Otherwise a database would be fine. For example BoltDB could be suitable. It is pure go and runs withing your program.
There are many approaches. You can use file and protect it with Go mutex or system lock. You can memory map the file for performance. You either can use BoltDB which is nice peace of software and provide needed machinery and can work in-process. If you write rare and mostly read, then constant DB https://github.com/colinmarc/cdb also looks interesting.
But, classic SQL DB has some advantages
You can use third party store for data and easely migrate when needed
You can access your data from third party app or just plain SQL
request
You can think about data schema and code logic separately
I'm rebuilding an app that supports customer specific templating (themes) from node.js to Go.
I'm currently using render to render my template files but what I actually need to do access templates that are stored in an object store such as Cloudfiles.
In node.js I've done this with express and I'm overriding the render() method but I've not been able to figure out how to do this in Go.
I essentially need to do something like this:
func (c *Controller) MyRouteHandler (rw http.ResponseWriter, req *http.Request) {
// retrieve the store from the context (assigned in middleware chain)
store := context.Get(req, "store").(*Store)
... do some stuff like load the entity from the database
// retrieve the template from the Object store and
// create the template instance (template.New("template").Parse(...))
tpl := c.ObjectStore.LoadTemplate(store, entity.TemplateFile)
// I know render's .HTML function takes the path to the template
// so I'll probably need to show the html a different way
c.HTML(rw, http.StatusOK, tpl, &PageContext{Title: "My Page", Entity: &entity})
}
I can dynamically include sub-templates by doing something like this if needed: http://play.golang.org/p/7BCPHdKRi2 but it doesn't seem like a great way if I'm honest.
I've searched for a solution to this but keep hitting road blocks. Any advice / assistance would be great.
Edit:
In essence, I'm asking the following:
How can I load a specific template from a datastore on a per-request basis.
How can I then send that as a response to the client
How can I load a specific template from a datastore on a per-request basis.
//take HTTP for example:
resp, err := http.Get("http://mytemplates.com/template1")
if err != nil {
// handle error
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
templateString := string(body)
How can I then send that as a response to the client
tmpl, err := template.New("name").Parse(templateString)
tmpl.Execute(rw, &yourDataModel{})