Need tests for (likely not a complete list):

* Test how InterestGroup values affected by k-anon checks are passed to generateBid.
  * adSizes, sizeGroups, ads, and adComponents all need such tests.
  * adSizes and sizeGroups currently have no tests, since they are incorectly
      currently not passed to generateBid at all.
* Test empty ads array:
   Maybe simplest to test its numBids is empty?  Hard to test a script isn't run.
* directFromSellerSignals.
    * The expected order when both responses use the same ad slot is currently
        undefined. However, we are in the process of resolving this matter by
        implementing a LIFO approach, as outlined in progress at
        crrev.com/c/4930438. Once this solution is in place, a test case will be
        created by fetching two different URLs with signals that share the same
        ad slot.
    * After adding new test cases for the component auction, test the
        directFromSellerSignals function with component auctions. Consider to
        set up one auction in the top frame and two component auctions. Send
        three fetch requests to retrieve three different AdAuctionSignals
        headers. Ensure that you use three different seller origins for the
        auctions and a different one for the buyer origin.
* All generateBid() and scoreAd() input parameters.
* All interest group fields (passed to auction, have effect on auction).
    Very few fields covered.
    Should be sure to cover buyerAndSellerReportingId and buyerReportingId for
        component ads, as they should not be settable.
    Already covered:
        Validation when joining/leaving interest group.
        renderURL and metadata for component ads (only integers covered, but
            probably not worth covering all types, if we have coverage for the
            main renderURL).
* Filtering/prioritization (including bidding signals influencing priorities)
* Size restrictions / ad and component ad sizes.
* additionalBids.
* adCost.
* bidCurrency.
* modellingSignals.
* Updates (both after auction and triggered).
* All auctionConfig parameters (including invalid auctionConfigs, and ones
    with no buyers).
* Joining interest group with duration of 0 should just leave the IG (not
    currently guaranteed to work, due to potential time skew between processes).
* Multiple buyers.
* Multiple interest groups with same owner.
* Multiple frame tests (including loading component
    ad URNs in fenced frames of other frames, etc)
* adAuctionConfig passed to reportResult().
* Component auctions.
  * Including cross-origin sellers.
* browserSignals fields in scoring/bidding methods.
* In reporting methods, browserSignals fields: topLevelSeller,
    componentSeller, modifiedBid, adCost, madeHighestScoringOtherBid
    (with interest group from another origin).
* Loading ads in iframes.
* In fencedframes window.fence.setReportEventDataForAutomaticBeacons()
* Automatic beacons (e.g., reserved.top_navigation)
* Network timeouts.
* Validate specific escaping behavior logic (still under discussion). There
    are a number of different rules for which characters are escaped, and
    whether spaces are escaped as "%20" or "+".
* Reports not sent if ad not used.
* Interactions with local network access API, which requires public
    networks to send CORS preflights for requests made over local networks.
    Needs testing with public publisher pages running auctions with
    sellers / buyers / update URLs on local networks.
* Calling FLEDGE APIs (or at least leaveAdInterestGroup() with no args)
    in a non-ad FencedFrame.
* Promise AuctionConfig parameters
* Test network requests in terms of fetch behavior
  * Network partition (not yet specced).
* Test that await is not needed for same-origin interest groups
  * Verify that's still in the spec/explainer first.
* executionMode
  * Including cross-origin join/leave behavior with "group-by-origin" mode.
* Make sure state is not shared.
  * Across scoreAd() / generateBid() calls, and with report calls.
  * In "group-by-origin" execution mode across IGs joined from different
      origins, and between generateBid() and reportWin().
* Test Content-Type headers allowed in responess for script/wasm/JSON fetches.
* Test WASM support, updating createBiddingWasmHelperURL().

If possible:
* Aggregate reporting.
* Join/leave permission delegation via .well-known files
  * Including tests for clearOriginJoinedInterestGroups().
  * Include tests for HTTP-y/fetch-y things (e.g., whether they have cookies)
* k-anonymity.
* Signals request batching. This is an optional feature, so can't require it,
    but maybe a test where batching could be used, and make sure things work,
    whether batching is used or not?