    @Test
    public void testLookupPackageSourceForMultiPkgsNegative() {

        Path filePath = RES_DIR.resolve("source").resolve("multipackages").resolve("sample").resolve("main.bal");
        Pair pair = compileAndGetWorkspacePackageRepo(filePath);
        Names names = pair.getNames();
        WorkspacePackageRepository workspacePackageRepository = pair.getWorkspacePackageRepository();

        //Prepare package ids
        Name orgName = names.fromString("demo");
        Name print = names.fromString("print");
        Name version = names.fromString("0.0.1");
        PackageID printPackageId = new PackageID(orgName, print, version);
        PackageID invalidPackageId = new PackageID(orgName, names.fromString("invalid"), version);

        PackageSource packageSource = workspacePackageRepository.lookupPackageSource(printPackageId,
                                                                                     "non-existent.bal");
        Assert.assertNull(packageSource);
        PackageSource packageSource1 = workspacePackageRepository.lookupPackageSource(invalidPackageId,
                                                                                      "io-printer.bal");
        Assert.assertNull(packageSource1);
    }