Is there a way to test belief?

Not really.

Historically, the only way to test this is torture, which we know to be ineffective.

Lie detector tests are just as unreliable and with a bit of training, they aren't that hard to fool.

An indirect way to test belief is by watching a person's actions. If they claim to believe in something but they don't ever behave as if they believe something, that can be an indicator, but not all beliefs have readily observable effects whether you hold them or not.

Atheists and theists do that here every day.

What you are really asking is, how can you test whether someone is telling the truth, when they say they have a certain belief. A polygraph might do the trick.

yes dear, you study scripture and follow the procedures to find God sincerely, and you can see if they work or not

God is doing that, as we speak.....

You are refrerring to those fake athesit claims ?

"According to the skin-conductance tests, the atheists found asking God to harm them or others to be just as upsetting as religious folks did. The researchers also compared the reactions of the atheists when making statements like 'I wish my parents were paralyzed' and 'I dare God to paralyze my parents.' Atheists were, like believers, more bothered by the latter statement, if you believe the skin-conductance tests, even though both declarations would be, in theory, equally empty if there were no heavenly overseer."

The study took place in Finland and was published in the International Journal for the Psychology of Religion under the title “Atheists Become Emotionally Aroused When Daring God to Do Terrible Things.”

Obedience.

Mark 9:7....Matthew 28: 19,20 and acts 5:42...

Depends on what you believe and if it is tangible or intangible.

Ask them to do something against their belief.

Of course. For example, I believe a bowling ball will hit all the cones if you roll it in a certain way. You can test that.

People tend to over complicate things, especially things that are not common knowledge,

“Belief” is simply something you think is true.

“Believing” is thinking something is true.

That’s basically what it is. Beliefs don’t only apply to religious people, they apply to everyone including atheists. Everyone has beliefs. And all beliefs come with faith. Faith is a feeling of trust. So even atheists have faith in their beliefs.