The problem started with an internal error in the database (HTTP
code 500, pq: duplicate key value) while trying to POST at /api/user
with body {"user":{newUserObject}} to the backend, that already had
three users User0 (Admin), UserA and UserB. Every test was
succeeding.
Eventually, the source of the problem was the initialization of the
field `ID` (primary key) of the embedded struct `Model` in model
`User`. When the `User` global variables User0, UserA and UserB
were created in `common/testdata.go` the `Model.ID` field was set
manually to the values 1, 2 and 3 respectively. This ofc was
unnecessary but those variables were used for comparison with the
relevant responses.
When gorm (or postgres, not entirely sure) have a new variable of a
model type, it will check if its primary key is zero (which means is
uninitialized) and will set it to the last used value +1. That means
that the new user that we were trying to insert in the DB got the
primary key value 1. This value was already in use by the User0 so
the DB refused to add the new user since there was a duplicate
primary key value. That's why we were getting an postgre's error and
HTTP 500.
Hence to fix the bug this commit:
- Removes `User.ID` initialization from `common/testdata.go`
- Omits the `User.ID` from the json marshaler by setting the struct
json tag to `json:"-"`. This is done because the request body is
compared to the response *after* is serialized by a call to
json.Marshal(). Since the `User.ID` is always uninitialized (value
0) the jsondiff.Compare() will always return a "NoMatch".
- Includes check for return of "SupersetMatch" in
NewTestEndpoint()'s jsondiff.Compare() call. Since the `User.ID` is
not serialized the json representation of the request will not
include an "id" key. On the contrary, the response *has* an "id" key
so it will always going to be a superset json object of the
serialized request.
- Modifies the validator's data struct to match the form of the
request ({"modelKey":{requestBody}}) by adding an intermediate
struct with the proper tag `json:"user"`.
- Decorates User model with json tags for marshaling.
- Introduces Model type same as gorm.Model with additional json tags
for marshaling.
- Modifies ResponseMsgUsers type.
- Modifies the testdata for the users by including initializer for
the Mode.ID field.
- The scenario test fails for those changes
