Ребзя не могу понять по каким строкам ещё оттестироваться можно. Если у вас есть варианты для тестирования подскажите пожалуйста. Вот мои тесты (по всем Ок):
Assert.assertTrue(Solution.isOneEditAway("Флаг","Флаг"));
Assert.assertTrue(Solution.isOneEditAway("",""));

Assert.assertTrue(Solution.isOneEditAway("Фла","Флаг"));
Assert.assertTrue(Solution.isOneEditAway("Флаг","Фла"));

Assert.assertTrue(Solution.isOneEditAway("лаг","Флаг"));
Assert.assertTrue(Solution.isOneEditAway("Флаг","лаг"));

Assert.assertTrue(Solution.isOneEditAway("Флваг","Флаг"));
Assert.assertTrue(Solution.isOneEditAway("Флаг","Флваг"));

Assert.assertTrue(Solution.isOneEditAway("Флаг","флаг"));
Assert.assertTrue(Solution.isOneEditAway("флаг","Флаг"));

Assert.assertTrue(Solution.isOneEditAway("01","91"));
Assert.assertTrue(Solution.isOneEditAway("01","091"));
Assert.assertTrue(Solution.isOneEditAway("01","1"));
Assert.assertTrue(Solution.isOneEditAway("091","91"));
Assert.assertTrue(Solution.isOneEditAway("123", "1023"));

//false
Assert.assertFalse(Solution.isOneEditAway("Флаг","Фиг"));
Assert.assertFalse(Solution.isOneEditAway("Фиг","Флаг"));

Assert.assertFalse(Solution.isOneEditAway("Флаг","Фиговый"));
Assert.assertFalse(Solution.isOneEditAway("Фиговый","Флаг"));

Assert.assertFalse(Solution.isOneEditAway("am", "mak"));

Assert.assertFalse(Solution.isOneEditAway("01", "102"));
Assert.assertFalse(Solution.isOneEditAway("2", "44"));
Assert.assertFalse(Solution.isOneEditAway("1234", "12367"));