False positive code coverage xcode 9/Swift 4

Im facing a little problem in a new Swift/Xcode project that I'm setting up. I'm actually implementing the CI tools for the project. One of the feature I'm monitoring for my pull requests is the code coverage of the project. I'm facing a bug when it come to the percentage of code covered by tests. Without having written any test, xcode code-coverage tool tells me that I have more than 82% of my code tested. This is obviously totally wrong since I haven't done any testing for the moment.

I'm wondering where does all this false positive detection comes from and how I could correct this problem. Some of my function seem to be marked as tested 6 time...

I'm actually using xcode 9.3 and my project is in swift 4.

Thank you in advance for any advice on the matter.

Best,

Martin