This is a bit of an incomplete look at the idea of a coronavirus.
Up until 2002, there were 4 known coronaviruses that affected humans. They produced symptoms of the common cold. When you say that people have been experiencing health problems for at least 30 years from coronaviruses, they were probably suffering from one of these 4 viruses.
(Keep in mind that there are
many more than 4 coronaviruses in the world. Different coronaviruses affect other animals, such as dogs, birds, pigs, or bats. However, only 4 coronaviruses actually affected humans.)
In 2003, a 5th coronavirus was identified in humans: SARS. SARS caused 8,096 cases and 774 deaths. [
source]
In 2012, a 6th coronavirus was identified in humans: MERS. MERS has caused about 2,494 cases and 858 deaths. [
source]
In 2019, a 7th coronavirus was identified in humans, and it was initially termed a "Novel" coronavirus because its features were different from the coronaviruses we knew up until that point.
Now, we know that 7th coronavirus as "SARS-CoV-2" and we know the disease it produces as "C0VlD-19."
So yes, they recently created a test to detect the presence of this new coronavirus. Because it was spreading to a lot of people and producing extreme disease symptoms, including organ failure and death.
The development of a test did not bring this coronavirus pandemic into the world.
The pathogen came into the world, and people responded by making a test.