As you may know this issue was being worked on here.

In the mean time what you could do to proceed with your tests is to use dependency injection with a mocked prisma client and to move the deconstruction line

const { PrismaClient } = pkg;

to where your class or function uses it inside an if, i.e:

class MyClass {
  prisma: Prisma.PrismaClient

  def constructor(props) {
    if (!props?.prisma) {
      const { PrismaClient } = Prisma
      this.prisma = new PrismaClient({
        log: ['error']
      })
    } else {
      this.prisma = props.prisma
    }
  }
}

I know its not ideal but hopefully this does the trick.

to mock the PrismaClient you could mock it using jest-mock-extended like so

const mockPrisma = mockDeep<OriginalPrismaClient>();