test

Description of the problem / feature request:

When overriding the copts and linkopts build configuration with None values in a transition, Bazel crashes with a NullPointerException.

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

def _my_transition_impl(settings, attr):
    return {
        "//command_line_

Currently, when entering epic mode the README is frozen in the last level of the tower. When you're trying to fine-tune the score for a level other than the last one, it would be helpful if we had the README for that level available. The proposal is that when entering epic mode, the README is updated with all levels, one following the other.

Example:

# Starbolt - beginner

我在测试时发现，华为荣耀NOTE8手机（4G内存），uiautomator2的版本号 2.13.0。在长时间循环调用d.screenshot()后（约每秒一次，调用一小时），手机内存会基本占满，手机明显卡顿。
调用adb shell dumpsys meminfo后，发现 EGL mtrack占用了2,309,408K。初步怀疑minicap 截图后不释放内存。目前只能重启手机解决。
恳请解决下。

I'd like an option for shouldEqualJson to ignore keys in actual that are unspecified in expected. It should probably be included for shouldNotEqualJson as well.

I think this could be achieved either by:

• Expanding CompareMode with new modes: CompareMode.StrictIgnoringUnknownKeys and CompareMode.LenientIgnoringUnknownKeys
• Adding a new flag to matcher signatures: `ignoreUnknown

A "normal" event on an instance ignores null subscriptions. If I do so on a substituted interface, a null subscription leads to an exception. I have a not so nice legacy code with different listeners to an event an one class that does null-attach internally under some conditions, would be nice if this behaviour would be able to be tested as well. Example code for the problem:

        publ