public async Task ReturnsNullIfTheWorkspaceIsNotPro(bool billableByDefault)
            {
                const long workspaceId = 11;
                var        workspace   = new MockWorkspace {
                    ProjectsBillableByDefault = billableByDefault
                };
                var feature = new MockWorkspaceFeature {
                    Enabled = false, FeatureId = WorkspaceFeatureId.Pro
                };
                var featureCollection = new MockWorkspaceFeatureCollection {
                    Features = new[] { feature }
                };

                Database.WorkspaceFeatures
                .GetById(workspaceId)
                .Returns(Observable.Return(featureCollection));
                Database.Workspaces
                .GetById(workspaceId)
                .Returns(Observable.Return(workspace));

                var projectsAreBillableByDefault =
                    await InteractorFactory.AreProjectsBillableByDefault(workspaceId).Execute();

                projectsAreBillableByDefault.Should().Be(null);
            }
            public async Task ChecksIfTheWorkspacesBillableByDefaultPropertyIfTheWorkspaceIsPro(bool billableByDefault)
            {
                const long workspaceId = 11;
                var        workspace   = new MockWorkspace {
                    ProjectsBillableByDefault = billableByDefault
                };
                var feature = new MockWorkspaceFeature {
                    Enabled = true, FeatureId = WorkspaceFeatureId.Pro
                };
                var featureCollection = new MockWorkspaceFeatureCollection {
                    Features = new[] { feature }
                };

                InteractorFactory.GetWorkspaceFeaturesById(workspaceId)
                .Execute()
                .Returns(Observable.Return(featureCollection));
                InteractorFactory.GetWorkspaceById(workspaceId)
                .Execute()
                .Returns(Observable.Return(workspace));

                var projectsAreBillableByDefault =
                    await InteractorFactory.AreProjectsBillableByDefault(workspaceId).Execute();

                projectsAreBillableByDefault.Should().Be(billableByDefault);
            }