Fren testinin yanı sıra far testi de yapıldı.

Yanı sıra is a common expression meaning besides, in addition to, or along with.

So the pattern is:

X-in yanı sıra Y de ...

= Besides X, Y also ...

In this sentence, fren testinin yanı sıra means besides the brake test / in addition to the brake test.

It is a fixed expression, so it is best learned as a chunk.

Because yanı sıra normally follows a noun phrase in the genitive form.

The pattern is:

• fren testi = brake test
• fren testinin yanı sıra = besides the brake test

So -nin is the genitive ending here.

A helpful way to think about it is:

• fren testi = the brake test / a brake test
• fren testinin yanı sıra = at the side of / besides the brake test

Even though the literal logic is a bit different from English, this is just the normal Turkish structure used with yanı sıra.

These are noun compounds, which are extremely common in Turkish.

• fren testi = brake test
• far testi = headlight test

In Turkish, when one noun modifies another noun, the second noun usually takes a compound ending:

• fren + test-i
• far + test-i

This is different from English, where we can often just place one noun before another without changing anything, as in brake test.

So testi here is not a separate word meaning something different; it is test with the compound ending.

Good question. The whole compound is being put into the genitive.

So the steps are roughly:

• fren testi = brake test
• fren testinin = of the brake test / the brake test’s

The genitive ending is added to the last word of the compound, not the first.

This is very normal in Turkish:

• araba kapısı = car door
• araba kapısının = of the car door

So fren testinin follows the same logic.

Here de means also or too.

So:

• far testi de = the headlight test also

It shows that this is an additional item. The idea is:

• not only the brake test
• but the headlight test as well

That is why de fits very naturally with yanı sıra.

Because this de is a separate particle meaning also/too.

It is not the same as the suffix -de/-da meaning in / at / on.

Compare:

• evde = in the house
• ev de = the house too

So in your sentence:

• far testi de = the headlight test too

Since it is the additive particle, it is written separately.

Yapıldı is the passive past form of yapmak.

Breakdown:

• yap- = do / make
• -ıl- = passive
• -dı = past tense

So yapıldı means was done or was carried out.

This is very common in reports, instructions, technical writing, and formal descriptions, where the action matters more than who did it.

So instead of saying someone did the headlight test, Turkish often says the headlight test was done.

Not always, but it is very common and often sounds more natural.

Compare:

• Fren testinin yanı sıra far testi de yapıldı.
• Fren testinin yanı sıra far testi yapıldı.

The second one is still understandable, but de makes the idea of addition clearer and stronger: the headlight test was also done.

So while it is not absolutely mandatory in every situation, it fits this sentence very well.

Yes, Turkish word order is flexible, but different orders can change the focus or emphasis.

This version is very natural:

• Fren testinin yanı sıra far testi de yapıldı.

It first sets up the reference point (besides the brake test) and then adds the new item (the headlight test too).

Another possible order would be:

• Far testi de fren testinin yanı sıra yapıldı.

This is possible, but the original sentence is more straightforward and neutral.

So the given order is a very natural way to present this information.

Turkish usually does not use articles the way English does.

So a phrase like far testi can mean:

• a headlight test
• the headlight test

The exact interpretation depends on context.

In this sentence, English will usually translate it with the because it sounds more natural in context, but Turkish does not need a separate word for that.