Although this question is more fit for ELL but I'll try to explain.
Active
Active voice describes a sentence where the subject performs the action stated by the verb.
For example:
John washed the dishes two hours ago.
Let's break it down:
- Subject: John
- Verb: washed (past)
- Object: the dishes
Therefore in active voice, you always have a subject (John) that is performing an action (Washing the dishes).
Passive
In passive voice sentences, the subject is acted upon by the verb.
Same example in passive voice:
The dishes were washed two hours ago.
Again breaking it down:
- Subject: The dishes
- Verb: were washed (passive past)
So as you see, in the passive voice, washing (verb) is acted upon the dishes (subject). By who? We don't know/care.
Active vs Passive voice? (When do we use them)
Usually, when the action itself is more important than the doer of the action, you use passive form.
Another situation would be, if you don't know who did an action or you don't care who did it, then you use passive.
So for example, When I say "The dishes were washed two hours ago.", I'm not saying who did it. Maybe because I actually don't know who did that, or maybe I don't care. Or maybe it's because it's not important who did it, the important thing is that they are washed.
In other situations, Active is usually preferred.
As stated by @Lynn in this answer, please keep in mind that:
In many styles of writing, active voice is preferred over passive voice for clarity and easier reading. However, in other styles of writing (particularly technical/legalese, which it sounds like you're quoting from), the more stilted sound of passive voice is more common - and perhaps even preferred.
Original Example:
You're (corrected) original line was:
If i run a test on my PC (I am a software tester) and it gets failed fails
Then you asked if you should say
"My test is failing" is a correct active sentence although its tense is not quite right. To fix the tense, you should instead say: "My test has failed." or "My test failed". (because it happened in the past)
For instance:
My test has failed because of a programming bug.
It's still active because as mentioned before, you have a subject (My test) that is doing something (failing).
This is not a correct passive voice. If you want to say it passively, you should instead say: "My test is failed". But it still sounds unusual. In this particular example, I'd use the active voice for clarity. You could definitely say something (passive) like:
If my test is failed, then...
But the active form is more clear and is preferred
If my test fails, then...
Conclusion
Use active for this particular example but as the rule of thumb, if you don't know when to use Active and when to use Passive, ask yourself which one is more significant. If the doer of the action is more important use active or if the action itself is more important, use passive.
Best Answer
In newspaper headlines, editors tend to leave out as many words as possible for space-economical reasons. It also helps readers to read the headlines very quickly to rouse their interest in reading the rest of the article.
So "A man was robbed while he was sitting at home" becomes:
Some standard parts of sentences that are left out of headlines are:
There are many more, and it can be an interesting exercise to try and reconstruct a complete, correct sentence out of condensed headlines :)
Although a bit of ambiguity is not bad for a headline (it helps attract attention), in this case I do not see ambiguity.
If slapped was meant as an active verb, I would have expected the object to be mentioned - otherwise it makes no sense.
"A man slapped his neighbour" would become "Man Slapped Neighbour", not "Man Slapped Visiting Neighbours House".
For a headline like "Company Sued for Millions", I also see little confusion: if it is the company doing the suing, it is only news while the case is ongoing, so it would be "Company Sues For Millions"