What I expected to happen was...:
The redstone should behave as it would in a normal block, yet the current would not go through.

What actually happened was...:
The current failed to go through.

Steps to Reproduce:
1. Place a slab in the top half of a block.
2. Place redstone on the slab.
3. Place redstone next to the slab ( Behind and infront is a good example)
4. Power one side
5. You will come to the conclusion its not working

PS
This was only tested in Minecraft Realms.