                     }
                 }
                 it("should return zero if delegate and dataSource are not set") {
+                    dataGridView.dataSource = nil
+                    dataGridView.delegate = nil
                     expect(layout.widthForColumn(0)) == 0
                 }
             }
 
             describe("heightForHeaderInSection") {
                 it("should return delegate's dataGrid:heightForRowAtIndexPath if present") {
-                    dataGridView.delegate = stubDelegate
                     expect(layout.heightForSectionHeader()) == stubDelegate.sectionHeaderHeight
                 }
 
                 it("should return it's rowHeight if delegate missing/not implements method") {
+                    dataGridView.delegate = nil
                     layout.sectionHeaderHeight = 120
                     expect(layout.heightForSectionHeader()) == 120
                 }

        describe("cells sizes") {
            describe("heightForRow") {
                it("should return delegate's dataGrid:heightForRow if present") {
                    dataGridView.delegate = stubDelegate
                    expect(layout.heightForRow(0)) == stubDelegate.rowHeight
                }

                it("should return it's rowHeight if delegate missing/not implements method") {
                    layout.rowHeight = 120
                    expect(layout.heightForRow(0)) == 120
                }


            describe("widthForColumn:") {
                it("should return delegate's dataGrid:widthForColumn:inSection: if present") {
                    expect(layout.widthForColumn(0)) == stubDelegate.columnWidth
                }
                it("should return equal widths for columns if delegate missing/not implements method") {
                    dataGridView.dataSource = stubDataSource
                    dataGridView.delegate = nil
                    stubDataSource.numberOfColumns = 7
                    // Ensure dataGrid width isn't devisible evenly on number of columns
                    let exactColumnWidth = frame.width / CGFloat(stubDataSource.numberOfColumns)
