CODEWITHSUNDEEP
dartflutter-test
Kryptix
Kryptix

Reputation: 197

Unit Testing Exceptions in Dart/Flutter

I'm trying to unit test using the given code.

test('Given Employee When employeeName less than 5 then throws Exception', () async {
    final employee = EmployeesCompanion.insert(
        employeeName: 'Tony',
        employeeCode: 'HR-121',
        address: '5th Floor, Park Avenue',
        contact: '1234567890',
        hiringDate: DateTime.now());
    expectLater(await employeesDB.createEmployee(employee),
        throwsA((f) => f.toString().contains('employeeName: Must at least be 5 characters long')));
  });

My unit test includes a predicate throwsA((f) => f.toString().contains('employeeName: Must at least be 5 characters long')) as given but dart fails this test with the exception:

package:moor/src/runtime/data_verification.dart 74:5                  VerificationContext.throwIfInvalid
package:moor/src/runtime/query_builder/statements/insert.dart 197:51  InsertStatement._validateIntegrity
package:moor/src/runtime/query_builder/statements/insert.dart 96:5    InsertStatement.createContext
package:moor/src/runtime/query_builder/statements/insert.dart 64:17   InsertStatement.insert
package:moor_ex/src/db/employees.dart 79:76                           EmployeesDB.createEmployee
test\employee_dept_test.dart 28:35                                    main.<fn>

InvalidDataException: Sorry, EmployeesCompanion(id: Value.absent(), employeeName: Value(Tony), employeeCode: Value(HR-121), address: Value(5th Floor, Park Avenue), contact: Value(1234567890), hiringDate: Value(2020-08-18 13:26:34.435349)) cannot be used for that because: 
• employeeName: Must at least be 5 characters long.

So what's the correct way to write this test in Dart?

Upvotes: 0

Views: 564

Answers (1)

lrn
lrn

Reputation: 71683

Try removing the await, or move it outside/before the expectLater.

The only difference between expect and expectLater is that the latter returns a future, but you ignore that future.

The expect/throwsA needs either a closure or a Future as the actual value, but you await that future so the await ... expression throws before you even call expectLater. Remove the await so you pass the Future to expectLater and the throwsA will then catch and match the error of that future.

So, I recommend changing it to:

  await expectLater(employeesDB.createEmployee(employee), ...

Upvotes: 1

Related Questions