First of all, anybody can edit wikipedia and on issues like what definitions of words to use its extremely difficult to coordinate. So using wikipedia as a source of authority is actually no very useful. Their are to many definitions and often people with a particular opinion edit, then other people who disagree edit it again.
One of the main issues is that their is the divide between countries that call them selfs socialist, and countries who are attempting a socialist model. Just as we understand that the "Democratic People's Republic of Korea" of North Korea is not actually a democratic or a Republic.
I define purely by economics system. So that means that North Korea actually has a socialist system but they no longer claim to be communist. China in turn calls itself socialist but their economic system has moved pretty far in the last 20 years (China is somewhat special because their are huge internal divides between special economic zones and some of other parts).
So I think that truly socialist in terms of economic policy, you basically only have North Korea and Cuba (Cuba could be different now, Im not very up to date). Venezuela never really went to the end but they certainly when pretty far. I don't know enough about Lao or Vietnam to make an educated comment about their economic policy.
For me a socialist government is one that is actively trying to get full control over the means of production. The more a government tries to attempted this, the more socialist they are. Lenin and co in 1917-1921 probably had the 'best' run. Within a very short time they nationalist banks, all major industry, all export, transportation and many others. The only thing they really failed to nationalise is the farmland because it was to difficult. It took Stalin to do that in 1928.
The definition of socialism as 'worker owned means of production' has been interpreted as 'means of production owned by a worker lead party' from a very early time. The follower of this definition have been by far the most successful socialist. The other interpretations had far less success.
As for Zimbabwe, yes the ZANU is a socialist party and the began to nationalise under the banner of socialism.