Even with 0 collateral deposits, user can take on trades and protocol will acquire bad debts

liquidation-test.ts

    ////Even with 0 collateral deposits, user can take on trades and protocol will acquire bad debts
    ////This test is in the context of JOJO unit test file -liquidation-test.ts-"check position"

    it("free riding position liquidatable", async () => {
      ////note: test preparation to ensure trader1 has zero deposits to begin the trade
      await context.dealer
        .connect(trader1)
        .requestWithdraw(utils.parseEther("5000"), utils.parseEther("5000"));
      await timeJump(100);
      await context.dealer
        .connect(trader1)
        .executeWithdraw(trader1.address, false);

      ////note: verify trader1 has zero deposits
      await checkCredit(context, trader1.address, "0", "0");
      ////note: price improved to trader1's favor at the point of order fill
      await context.priceSourceList[0].setMarkPrice(utils.parseEther("31000"));
      ////note: open position and trade
      await openPosition(
        trader1,
        trader2,
        "1",
        "30000",
        context.perpList[0],
        orderEnv
      );
      ////note: trader1 is in good standing after trade with 0 collateral tokens
      expect(await context.dealer.isSafe(trader2.address)).to.be.true;
      expect(await context.dealer.isSafe(trader1.address)).to.be.true;
      await checkCredit(context, trader1.address, "0", "0");
      await checkBalance(context.perpList[0], trader1.address, "1", "-30015");

      await context.priceSourceList[0].setMarkPrice(utils.parseEther("20000"));
      ////note: trader1 is liquidatable after price change
      expect(await context.dealer.isSafe(trader1.address)).to.be.false;
      expect(await context.dealer.isSafe(trader2.address)).to.be.true;
     
      const liquidatorChange = await context.dealer.getLiquidationCost(
        perp0.address,
        trader1.address,
        utils.parseEther("1")
      );
      expect(liquidatorChange.liqtorPaperChange).to.be.equal(
        utils.parseEther("1")
      );
      expect(liquidatorChange.liqtorCreditChange).to.be.equal(
        utils.parseEther("-19800")
      );
      await checkCredit(context, insurance, "0", "0");
      await perp0
        .connect(liquidator)
        .liquidate(
          liquidator.address,
          trader1.address,
          utils.parseEther("1"),
          utils.parseEther("-20000")
        );
      await checkBalance(perp0, liquidator.address, "1", "-19800");
      await checkBalance(perp0, trader1.address, "0", "0");
      await checkCredit(context, insurance, "-10215.00", "0");
      ////!!!: insurance accrued by bad debts and insurance fee is not able to cover bad debts
      await checkCredit(context, liquidator.address, "0", "5000");
      await checkCredit(context, trader1.address, "0", "0");
      expect(await context.dealer.isSafe(trader1.address)).to.be.true;
    });