How to access a Dart class in a unit test

Question

Using Dart Milestone 4 version 21658

I'm new to Dart. I created a class. I want to unit test it. Both the class and the unit test are in the same Dart project created using the Dart Editor. I don't know how to make the unit test see my class. How can I do this?

Project Name: DartExp

Directory structure:

src/foo.dart
test/foo_test.dart

File contents:

--- foo.dart begin ----

//library foo;

class Foo
{
  String bar;
}

--- foo.dart end ----

--- foo.dart begin ----

import 'package:unittest/unittest.dart';

import 'package:DartExp/foo.dart';
import 'DartExp/foo.dart';
import 'foo.dart';
import 'src/foo.dart';
import 'package:src/foo.dart';

main() {

  test('test Foo', () {

     Foo foo;

     //expect(1,1);
   });
}

--- foo.dart end ----

Things I've tried:

In the Dart Editor, in the file foo_test.dart, all my attempts to import foo.dart are marked as error because "...is not valid uri". The editor also says the class Foo is undefined. Removing all the foo.dart import statements, doesn't work either. Making foo.dart into a library doesn't work either.

Documentation of the Dart import statement doesn't seem to give any examples for this common use case.

So, how do you import a class into a unit test in Dart?

@Greg: Thank you for taking time to answer my question. Your answer made me see (and correct) a mistake in my original problem statement. The unit test foo_test.dart is actually in the 'test' directory and not in 'lib'. Sorry for the incorrect info. — devdanke

Greg Lowe Greg Lowe · Accepted Answer · 2013-04-22T01:34:20

Dart uses the Pub package manager for dependency management, and has a specific suggested package layout, which you can read about on the Pub website.

Try this and also run pub install.

Directory structure:

pubspec.yaml
lib/foo.dart
test/foo_test.dart

pubspec.yaml

name: my_package
description: description
dev_dependencies:
   unittest: any

lib/foo.dart:

library foo;

class Foo {
}

test/foo_test.dart:

import 'package:unittest/unittest.dart';
import 'package:foo/foo.dart';

main() {
  test('test Foo', () {
     Foo foo;
   });
}

The package: URLs are resolved from the packages directory that Pub creates. To better understand this have a look at the contents of the packages directory after you run pub install.

So this:

import 'package:[package-name]/[file].dart';

Imports a library which is in the package named [package-name], and found in the lib folder of this package in a file named [file].dart. (Note: a package can have multiple libraries.)

How to access a Dart class in a unit test

2 Answers